Cook the rice: prepare the 1 cup cilantro lime rice according to the recipe (or use 1 cup cooked cilantro lime rice you have on hand). Keep it warm.
Cook the vegetables: heat a small pan over medium-high to high heat. Add 1 teaspoon olive oil, then the 1/2 onion (sliced) and 1/2 bell pepper (sliced). Season with salt and pepper to taste and cook, stirring occasionally, for 3–4 minutes or until the edges begin to brown. Turn off the heat and set the pan aside.
Prepare the avocado and beans: if the avocado is not already sliced, slice the 1 ripe avocado. Drain/rinse the 1/2 cup pinto or black beans if desired.
Warm the tortillas: warm the 2 large flour tortillas briefly so they are pliable (microwave 15–20 seconds or heat 20–30 seconds per side in a dry skillet).
Divide the fillings: divide the cooked rice, cooked vegetables, avocado slices, beans, sour cream, and salsa between the two tortillas as follows: - Rice: 1/2 cup rice per tortilla (half of the 1 cup). - Veggies: half of the cooked onions and peppers per tortilla. - Avocado: half of the sliced avocado per tortilla. - Beans: 1/4 cup beans per tortilla (half of the 1/2 cup). - Sour cream: 2 tablespoons sour cream per tortilla (total 1/4 cup). - Salsa: 1 tablespoon Mexican salsa per tortilla (total 2 tablespoons). - Add salt and pepper to taste.
Assemble each burrito: lay one warmed tortilla flat, place the rice in a line down the center, top with the vegetables, avocado slices, beans, 2 tablespoons sour cream, and 1 tablespoon salsa. Season lightly with salt and pepper.
Fold and roll: fold the left and right sides of the tortilla over the filling, then roll the tortilla away from you, tucking as you go, until the burrito is closed.
Serve: wrap each burrito in foil if desired, then cut each burrito in half and serve warm.