Rinse the rice under cold water until the water runs clear, then drain well.

Combine the rinsed rice and 3 cups of water in a rice cooker or pot. Cook according to rice cooker instructions or bring to a boil, cover, reduce heat to low, and simmer for 18 minutes until water is absorbed and rice is tender. Remove from heat and let it stand covered for 5 minutes.

Heat the olive oil in a large skillet over medium heat. Add the chopped onion and cook until softened, about 3-4 minutes.

Add the minced garlic and cook for another 30 seconds until fragrant.

Add the ground beef to the skillet and cook, breaking it apart with a spatula, until browned and cooked through, about 6-8 minutes.

Drain excess fat if necessary, then stir in chili powder, cumin, paprika, oregano, salt, and black pepper until well combined.

Pour in 1/4 cup water, reduce heat to low, and let the mixture simmer for 5 minutes to allow the flavors to meld and the liquid to reduce slightly. Remove from heat and keep warm.

Fluff the cooked rice with a fork and evenly divide it between four bowls.

Top each bowl of rice with a generous portion of the seasoned ground beef.

Add toppings evenly: shredded lettuce, cherry tomatoes, corn kernels, black beans, and shredded cheddar cheese.

Garnish with chopped cilantro if using, and add a dollop of sour cream on the side.

Serve each bowl with a lime wedge for squeezing fresh juice over just before eating.