Slice tomatoes into wedges; set aside.
Cut flank steak into 1/4-inch thick slices.
In a shallow pan, combine white wine, lime juice, grated lime peel, crushed garlic cloves, salt, and crushed red pepper flakes. Stir in the beef, sliced onions, sliced green bell pepper, and sliced yellow bell pepper; mix gently and let stand for 20 minutes.
Preheat the broiler. Remove the beef and vegetables from the marinade and place on a broiler pan in a single layer.
Broil 3 to 4-inches from the heat until browned, about 2 minutes. Using a spatula, turn the beef and vegetables add the reserved tomatoes. Broil until the beef is done, about 2 minutes. Serve in warmed flour tortillas with shredded Monterey Jack cheese, sour cream, and sliced avocado.
Servings: 5