Combine steak, onion and red pepper in shallow dish. Combine garlic, lime juice, oil, vinegar, cilantro, cumin and salt in small bowl. Pour over steak and vegetables; toss. Cover and refrigerate for 1 to 2 hours.
Preheat broiler. Broil steak 6 inches from heat for 8 to 10 minutes on one side; turn over. Add vegetables with remaining marinade. Broil 10 minutes more or until meat is done to desired doneness and vegetables are cooked.
Let meat stand 10 minutes. Cut diagonally against grain into thin slices. Mound steak and vegetables into tortillas; fold and serve.