Preheat the oven to 375°F (190°C) and lightly coat a dark-colored sheet pan with cooking spray.
Heat the olive oil in a large skillet over medium-high heat.
Add the finely diced onion and sauté until golden, about 3 minutes, pushing the onion to the pan edges.
Add the ground beef to the center of the skillet, sear until browned, then break up and cook through, about 3–5 minutes; drain excess grease if needed.
Reduce heat to medium, stir in the taco seasoning, and cook 1–3 minutes until fragrant.
Pour in the enchilada sauce, simmer until the mixture thickens slightly, then remove from heat and stir in the drained and rinsed black beans if using; let cool slightly.
Warm the refried beans if desired (microwave or stovetop) so they’re easy to spread.
Lay out a tortilla, spread a portion of refried beans down the center, add some cilantro-lime or white rice, then top with the seasoned beef mixture and a sprinkle of shredded Cheddar.
Fold the sides of the tortilla in, then roll tightly to form a burrito; repeat with remaining tortillas and fillings.
Lightly spray each rolled burrito with cooking spray and place them spaced apart on the prepared sheet pan.
Bake at 375°F for 8 minutes, flip each burrito, then bake an additional 5 minutes until crisped.
Let the burritos rest about 5 minutes before serving, and serve with desired toppings such as sour cream, avocado or guacamole, pico de gallo, and salsa.
Optional: Instead of baking, crisp burritos in a skillet over medium heat until golden on both sides.
