In a medium saute pan over medium heat, add 1 tablespoon of the olive oil and, when hot, saute the onion, bell pepper, and garlic until softened, 3 to 4 minutes. Add the cumin, salt, and chili powder and cook for 2 minutes longer, until vegetables are lightly golden. Remove from the heat and set aside.

Lay the tortillas on a clean work surfact and divide half of the cheese evenly among one side of each tortilla, then top them with the beans, dividing them evenly among the tortillas. Sprinkle the remaining cheese over the beans, and sprinkle each tortilla with chili powder. Fold the tortillas to close. Preheat a large nonstick skillet over medium-high heat. Brush the tortillas on both sides with some of the remaining oil.

Working with 2 at a time, place the filled tortillas in the hot pan and cook until golden brown and crisp on the bottom. Carefully flip the tortillas over and continue to cook until golden on the second side and the cheese is melted and filling is heated through. Repeat with the remaining tortillas. Serve immediately, garnished with the salsa, guacamole, and sour cream.