01 - Heat olive oil in a large skillet over medium heat. Add chopped onion and sauté until softened, about 3 minutes. Add minced garlic and cook for 1 minute more until fragrant.
02 - Add ground beef to the skillet, breaking it up with a spatula. Cook until browned, about 6-8 minutes. Drain excess fat if necessary.
03 - Stir in cumin, chili powder, smoked paprika, oregano, salt, pepper, and tomato sauce. Simmer for 3-4 minutes until thickened. Remove from heat.
04 - In another skillet, combine cooked rice, black beans, cumin, chili powder, and lime juice. Warm over low heat for 2-3 minutes, stirring occasionally. Season with salt and pepper to taste.
05 - Heat tortillas in a dry skillet for 30 seconds per side or microwave until pliable. Keep warm covered with a clean towel.
06 - Lay a tortilla flat and spoon a quarter of the rice and bean mixture onto the center. Top with a quarter of the beef, cheese, lettuce, and tomato. Add a dollop of sour cream and sprinkle with cilantro if desired.
07 - Fold in the sides of the tortilla, then roll up tightly from the bottom to form a secure burrito. Repeat with remaining tortillas and fillings.
08 - Serve immediately with extra salsa or hot sauce on the side. Burritos can be wrapped in foil and kept warm in a low oven until ready to serve.