Place meat in shallow glass dish. Sprinkle with lime juice, Worcestershire and garlic mashed with salt. Cover and marinate in refrigerator 1 hour.
In large salad bowl, combine lettuce, onions, croutons, tomato, avocado and cheese. In small bowl, whisk together oil, lime juice, chili powder, garlic salt and sugar.
Grill or broil steak about 2 minutes on each side or to desired doneness.
Slice thinly at an angle across grain.
Toss salad lightly with dressing, arrange meat over top.