In a small mixing bowl, combine salsa, garlic, lime juice, salt and pepper.
Place flank steak in a 4-quart crockpot, and pour sauce over steak, making sure to coat steak well. Add bell peppers and onion. Cover and cook on LOW heat setting for 6 to 8 hours or on HIGH heat setting for 3 to 4 hours.
Remove steak and vegetables from juice and let steak stand 10 minutes before slicing. Slice steak thinly across grain of meat.
Serve with peppers and onion. Garnish with fresh cilantro. Pass warm flour tortillas, rice and beans.
Servings: 6