Preheat the oven to 375°F (190°C).
Bring a large pot of water to a boil. Add the bell peppers and cook for 3 minutes to soften slightly. Remove and drain upside down on paper towels.
Heat olive oil in a large skillet over medium heat. Add the chopped onion and cook for 3 minutes until softened.
Add the minced garlic and cook for 1 minute until fragrant.
Add the ground beef to the skillet. Cook, breaking it up with a spoon, until browned and cooked through, about 6-8 minutes.
Stir in ground cumin, chili powder, smoked paprika, salt, and black pepper. Cook for 1 minute to toast the spices.
Remove the skillet from heat. Stir in cooked rice, black beans, corn, diced tomatoes, and half of the shredded cheddar cheese until well combined.
Place the bell peppers upright in a baking dish. Spoon the beef and rice mixture evenly into each pepper, packing gently.
Sprinkle the remaining shredded cheddar cheese on top of each stuffed pepper.
Cover the baking dish with aluminum foil and bake for 25 minutes.
Remove the foil and bake for an additional 10-15 minutes until the cheese is melted and bubbly.
Remove from the oven and let cool for 5 minutes.
Garnish with chopped fresh cilantro and serve with lime wedges on the side.