Tender Flat Iron Steak gets a flavor kick from a simple salsa marinade before being sliced and placed atop corn chips for an impressive appetizer.
Place beef Flat Iron Steaks and 1/2 cup salsa in food-safe plastic bag; turn steaks to coat. Close bag securely and marinate in refrigerator 15 minutes to 2 hours. Combine remaining 1/2 cup salsa and chopped cilantro, as desired; cover and refrigerate until ready to use.
Remove steaks from marinade; discard marinade. Place steaks on grid over medium, ash-covered coals. Grill, covered, 10 to 14 minutes (over medium heat on preheated gas grill, 12 to 16 minutes) for medium rare (145°F) to medium (160°F) doneness, turning occasionally.
Carve steaks into thin slices; cut slices into bite-size pieces. Arrange chips on platter. Top each chip evenly with reserved salsa mixture, beef and guacamole. Garnish with cilantro leaf, if desired. Serve immediately.