Preheat the oven to 375°F (190°C).
Cut the tops off the bell peppers and remove the seeds.
In a skillet, sauté the chopped onion and minced garlic until translucent.
Add the cooked rice, diced tomatoes, black beans, and corn to the skillet.
Stir in cumin, paprika, salt, and pepper.
Mix everything well and cook for about 5 minutes.
Stuff the bell peppers with the rice mixture.
Place the stuffed peppers upright in a baking dish.
Add a splash of water to the bottom of the dish to keep them moist.
Bake for 25-30 minutes until the peppers are tender.