Combine cumin and garlic; press evenly onto beef steaks.
Place steaks on grid over medium, ash-covered coals. Grill, covered, 11 to 14 minutes (over medium heat on preheated gas grill, 11 to 15 minutes) for medium rare (145°F) to medium (160°F) doneness, turning occasionally.
Squeeze juice from 1 lime wedge over each steak. Carve steaks into thin slices. Serve with guacamole; garnish with lime wedges, if desired.
Cook's Tip: To broil, place steaks on rack in broiler pan so surface of beef is 3 to 4 inches from heat. Broil 13 to 17 minutes for medium rare (145°F) to medium (160°F) doneness, turning once.