Add sliced bell peppers and cook for 4-5 minutes until tender. Stir in tomato paste, soy sauce, paprika, cumin, pepper, and red pepper flakes if using. Cook for 2 minutes.
Add cooked rice and stir to combine. Cook for another 2-3 minutes to meld flavors. Serve hot with optional toppings.
Notes
For extra flavor, garnish with fresh herbs or a squeeze of lime.