In a saucepan, bring the water to a boil. Add quinoa, reduce heat to low, cover, and simmer according to package instructions, usually around 15 minutes, or until the quinoa is cooked and the water is absorbed.

Preheat oven to 375°F (190°C).

In a large skillet, heat oil over medium heat. Add the onion and cook until softened, 5-7 minutes. Add the garlic and cook until fragrant, about 1 minute. Stir in the black beans, diced tomatoes, corn, cooked quinoa, cumin, chili powder, and smoked paprika. Cook for 2-3 minutes, until heated through. Season with salt and pepper to taste.

Cut the tops off the bell peppers and remove the seeds and membranes. Stuff each bell pepper with the quinoa mixture and place them upright in a baking dish.

Cover the dish with aluminum foil and bake for 30 minutes.

Remove the foil, sprinkle cheese over the stuffed peppers, and bake for an additional 10-15 minutes, or until the peppers are tender and the cheese is melted. Serve.