Heat the olive oil in a large skillet over medium heat. Add the chopped onion and sauté until translucent, about 3-5 minutes.
Stir in the minced garlic and diced bell pepper, cooking for 2 minutes until the pepper softens.
Add the black beans to the skillet along with the cumin, chili powder, smoked paprika, salt, and pepper. Cook for 5 minutes, stirring occasionally, allowing the flavors to meld.
Warm the flour tortillas in a separate pan or microwave to make them more pliable.
Lay out the tortillas and evenly distribute the cooked rice onto each one, followed by the black bean mixture.
Sprinkle shredded cheese over the beans and rice, then add cilantro and a spoonful of salsa.
Add a dollop of sour cream and a few slices of avocado to each burrito if desired.
Fold the sides of the tortilla in, then roll up the burrito tightly, tucking in the ends.
Serve the burritos warm, with lime wedges on the side for squeezing over the top.