Combine marinade ingredients in small bowl.
Remove and reserve 2 tablespoons for topping; cover and refrigerate.
Place beef steak and remaining marinade in food-safe plastic bag; turn steak to coat.
Close bag securely and marinate in refrigerator 6 hours or as long as overnight, turning occasionally.
Preheat grill to medium.
Remove steak from marinade; discard marinade.
Place steak on grid and grill, uncovered, 10 to 13 minutes for medium rare to medium doneness, turning occasionally.
Meanwhile combine corn, tomato, 2 tablespoons cilantro, salt and reserved marinade in medium bowl. Set aside.
Remove steak; keep warm.
Place tortillas on grid. Grill, uncovered, 2 to 3 minutes or until bottoms are evenly toasted, rotating tortillas around grid as needed to prevent over-browning.
Turn tortillas over; sprinkle evenly with cheese. Grill 1 to 3 minutes or until bottoms are toasted and cheese starts to melt, rotating around grid as needed.
Carve steak diagonally across the grain into thin slices.
Season with salt, as desired.
Top tortillas with equal amounts of beef and corn mixture.
Garnish with cilantro, if desired.
