Rinse the rice under cold water until the water runs clear.
In a medium saucepan, bring 2 cups of water to a boil. Add the rice, reduce heat to low, cover, and simmer for 15 minutes or until the rice is tender and water is absorbed. Remove from heat and let stand covered for 5 minutes.
While the rice cooks, heat olive oil in a large skillet over medium-high heat.
Add the chopped onion and cook for 3-4 minutes until softened.
Add the minced garlic and cook for 30 seconds until fragrant.
Add the ground beef to the skillet. Cook, breaking it apart with a spoon, until browned and cooked through, about 6-8 minutes.
Drain any excess fat from the skillet.
Stir in chili powder, ground cumin, smoked paprika, dried oregano, salt, and black pepper. Cook for 1 minute to toast the spices.
Add the diced tomatoes, black beans, and corn to the beef mixture. Stir to combine and cook for another 3-4 minutes until heated through.
Fluff the cooked rice with a fork and divide it evenly among four bowls.
Top each bowl of rice with the seasoned ground beef mixture.
Sprinkle shredded cheddar cheese over the warm beef mixture to allow it to melt slightly.
Add shredded lettuce and diced tomato on top.
Garnish with chopped fresh cilantro and a dollop of sour cream.
Serve each bowl with a lime wedge to squeeze over before eating.