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Spicy Tuna Onigiri

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You've got to try this spicy tuna onigiri recipe! It's the most delicious and comforting snack that can be eaten for lunch (think of them as a rice sandwich).

Onigiri are Japanese rice balls that are often shaped as triangles but they can be pressed into other shapes as well.

These onigiri are stuffed with a tuna, mayo, and sriracha mixture and then topped with furikake.

Four spicy tuna onigiri sitting on a green plate.

What is Onigiri & Why You'll Love it

Onigiri are a popular Japanese snack that includes a rice ball, stuffed with delicious fillings and wrapped in nori sheets. They're an easy way to enjoy a delicious and filling snack.

They're available at most convenience stores in Japan and have hundreds of different filling types and wrappers. Popular fillings include umeboshi (pickled plum), salted salmon, bonito flakes, or seaweed.

These tuna onigiri are also a Japanese favorite, and when you make them, you'll see why! You can eat these warm or cold, but I enjoy them warmer. They're super tasty, comforting, and filling.

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Spicy tuna onigiri ingredients.

Steamed Rice - You'll need 4 cups of cooked sushi rice or other small-grained white rice. The smaller grained rice holds together better. You must use rice that is still warm after cooking it. Rice that has cooled off or been in the refrigerator will not hold together.

Tuna - You'll use 5 ounces of canned tuna of your choice.

Kewpie Mayonnaise - You'll need 2 tablespoons of Kewpie mayo. Using regular mayonnaise will not give you the savory flavor that Kewpies does!

Sriracha - You'll need 1 tablespoon of sriracha or other hot chili sauce. If you love spicy food, you can add another tablespoon.

Nori seaweed sheets - You'll cut the nori to make strips for the base of the onigiri. This is so you have a place to hold them while eating them that's not sticky.

Seasonings - You can use an optional 1 tablespoon of rice vinegar to season the rice. I love the flavor it adds, but if you don't have it, you can leave it out. You'll also need a pinch of salt and 2 tablespoons of furikake seasoning (a Japanese rice seasoning).

How to Make Onigiri

Make the rice - Prepare your rice according to package directions, and while it's hot, add the rice wine vinegar. A rice cooker works great, but you can prepare on the stovetop too. 

Prepare the filling - Combine the tuna, Kewpie mayonnaise, sriracha, and salt in a small bowl. Stir till incorporated.

Spicy tuna mixture in a white bowl.

Press the rice - Wet your hands with cold water. Then press ⅓ cup of rice into your palm or an onigiri mold. Press your thumb into the rice to create a well.

Stuff with filling - Fill the well in the rice with 1 tablespoon of the tuna filling.

Add more rice - Cover the tuna with 2 ½ tablespoons of rice.

Press on the lid - Press the lid gently onto the rice.

Remove from mold - Remove the lid, flip the mold over, and press the base to release the onigiri from the mold.

Three pictures showing how to make onigiri.

Cut the nori - Cut eight 3 inch long and 1 inch wide strips from the nori.

Add the nori - Wrap a strip of nori around the base of each onigiri.

Dip in furikake - Sprinkle the furikake on a plate or cutting board and carefully dip the sides of the onigiri onto it to coat them in a thin layer. If you like a little spice, you can add red pepper flakes. 

I like to eat my onigiri immediately when they're still warm, but you can save them for several days in the refrigerator. 

Frequently Asked Questions

What can I put inside onigiri?

Creamy, spicy mayo tuna is my favorite onigiri filling, but other popular onigiri fillings are umeboshi (pickled plum), salted salmon, bonito flakes, or seaweed. 

How to make onigiri without a mold?

If you don't have a triangular onigiri mold on hand, you can shape the sticky rice with wet hands into the shape of a triangle and place on plastic wrap. Wrap the rice with the plastic wrap and shape. The wrap will help you get the triangle shape. 

Is onigiri served cold?

Onigiri can be served cold or warm. Onigiri were created before refrigerators as a way to preserve rice, so they are often consumed at room temperature.

Can onigiri be frozen?

Onigiri can be frozen but should be individually wrapped in plastic before being put in the freezer. Also, don't freeze nori on the onigiri, it will come out soggy. Add any nori you'd like to use after you defrost them.

How long does onigiri last?

Onigiri will last in the refrigerator for up to 5 days, but they are best eaten the day they are made as they tend to get clumpy or crumbly in the refrigerator. Onigiri can sit out at room temperature for up to 4 hours.

Is onigiri rice the same as sushi rice?

Technically onigiri rice and sushi rice are not the same (sushi rice is a certain type of rice that's also made with a vinegar, sugar salt mix), but the best rice to use for onigiri is sushi rice (Koshihikari or Japanese short-grain rice). Sushi rice has a plump texture that sticks together when pressed, making it great for onigiri. You can also use other types of white, short-grained rice like arborio if you can't find sushi rice. Jasmine rice isn't recommended, as it doesn't stick together well. 

Why is my onigiri falling apart?

Onigiri fall apart for two reasons - the rice was either not the right type or the right temperature. The rice needs to be a smaller, stickier rice type like sushi rice or arborio and the onigiri need to be made when the rice is still warm from being cooked.

A hand holding an onigiri with a bite taken out of it.

Tips for Making this Recipe

  • Specialty Ingredients - For the best results, I highly recommend using Japanese sushi rice. It will help the rice balls stick together, and it has great flavor.
  • Recommended Tools - If you are new to making onigiri, I highly recommend purchasing an onigiri press as they are cheap and help you make the perfect shape!
  • Storing Tips - Onigiri are best eaten the day they are made, but if you would like to save them you can refrigerate them in an airtight container for up to four days or freeze them. For both, you need to individually wrap each piece before placing it in the fridge or freezer. Remove any nori before refrigerating or freezing as it will become soggy.

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Yield: 8 pieces

Spicy Tuna Onigiri

Four spicy tuna onigiri on a green plate.

These delicious Japanese rice balls can be eaten as a snack or main meal, since they are stuffed with a filling tuna mixture.

Prep Time 10 minutes
Additional Time 15 minutes
Total Time 25 minutes


  • 4 cups cooked sushi rice*
  • 1 tablespoon rice wine vinegar
  • 1 (5-ounce) can of tuna
  • 2 tablespoons Kewpie mayonnaise
  • 1 tablespoon sriracha or other chili paste
  • pinch of salt
  • 1 sheet of nori
  • 2 tablespoons furikake seasoning


  1. Pour the rice wine vinegar onto the rice and stir to combine.
  2. Combine the tuna, kewpie mayonnaise, sriracha, and salt in a bowl and stir till combined.
  3. Wet your hands and then press ⅓ cup of rice into your palm or an onigiri mold. Press your thumb into the rice to create a well. Fill this with 1 tablespoon of the tuna mixture, then cover with 2 ½ tablespoons of rice. Press the rice to combine and then mold into a triangular shape, or if using an onigiri mold, press the lid onto the rice and then release it from the mold.
  4. Repeat till all rice and tuna are used.
  5. Cut the nori into strips 3 inch long strips that are 1 inch wide. Wrap them around the base of the onigiri.
  6. Sprinkle the furikake onto a plate and dip the sides of the onigiri to coat them with a thin layer of furikake.
  7. Serve immediately or save in the refrigerator (wrapped in plastic wrap) for up to 3 days.


*Or other small-grained white rice. Jasmine and other long-grain kinds of rice are not recommended.

Nutrition Information:



Serving Size:


Amount Per Serving: Calories: 172Total Fat: 4gSaturated Fat: 1gTrans Fat: 0gUnsaturated Fat: 3gCholesterol: 6mgSodium: 402mgCarbohydrates: 28gFiber: 0gSugar: 5gProtein: 5g

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