Step 1

Score both sides of steak in a diamond pattern by making shallow diagonal cuts at 1-inch intervals. Place steak in a resealable plastic bag set in a shallow dish.

Step 2

In a screw-top jar, combine salad dressing, lime peel, lime juice and cilantro. Cover and shake well. Pour half of the salad dressing mixture into a small bowl and add onion; cover and chill until serving time. Pour the remaining salad dressing mixture in the jar over steak in bag. Seal bag; turn to coat steak. Marinate in the refrigerator for 24 hours, turning bag occasionally.

Step 3

Drain beef, discarding marinade. Sprinkle with salt and black pepper. For a charcoal or gas grill, grill steak on the rack of a covered grill directly over medium heat for 17 to 21 minutes for medium doneness (160 degrees F), turning once halfway through grilling time.

Step 4

To serve, thinly slice beef across grain. In a large bowl toss together beef, salad greens, sweet pepper, avocado and the dressing-onion mixture. Divide beef mixture among pita halves.

Tips

Preheat broiler. Place steak on the unheated rack of a foil-lined broiler pan. Broil 3 to 4 inches from the heat for 15 to 18 minutes for medium doneness (160 degrees F), turning once halfway through broiling time.