Heat 1 tablespoon of olive oil in a large frying pan or skillet over medium heat.
Add the onion to the pan and cook for 3 to 4 minutes or until translucent. Then add the diced bell pepper and cook for 3 more minutes. Add the garlic and ginger, and cook, stirring constantly, for 30 seconds.
Add the curry powder, salt, red pepper flakes, and black pepper. Stir for 30 seconds.
Pour in the coconut milk and diced tomatoes. Stir till combined and all coconut milk is combined.
Add the shrimp into the pot. Stir gently to coat all the shrimp. Increase the heat and bring the mixture to a low boil, reduce the heat and allow to simmer for 10 minutes. Stir occasionally.
Turn off the heat and top with optional herbs.
Optional - serve with white or brown rice and top with sliced chiles and slices of lime.