Place the rice and 2 cups water in a medium saucepan. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until the water is absorbed. Remove from heat and let it sit covered.
While the rice cooks, heat the olive oil in a large skillet over medium heat. Add the diced onion and cook for 3 minutes until it softens.
Add the ground beef to the skillet. Break it up with a spoon and cook for 5 to 6 minutes until browned. Stir in the minced garlic and cook for 1 minute more.
Stir the chili powder, cumin, salt, and black pepper into the beef mixture. Add the black beans and salsa. Cook for 4 minutes, stirring occasionally, until everything is heated through.
Fluff the rice with a fork. Divide the rice among four bowls. Spoon the beef and bean mixture over the rice.
Top each bowl with shredded cheddar cheese, diced avocado, and chopped cilantro. Serve with lime wedges on the side.