In a large nonstick skillet over medium-high heat, cook the beef, onion, and garlic until the beef is browned. Drain the fat.
Stir in the beans, chile pepper, and chili powder, and cook until hot. Remove from the heat.
Warm the tortillas in the microwave for 20 seconds, then fill each tortilla with half the mixture. Top with lettuce, tomatoes, and cheese, and roll each tortilla tightly into a tube.
