Marinate the flank steak in balsamic vinegar, olive oil, garlic powder, salt, and pepper for at least 30 minutes.
Preheat the grill to medium-high heat.
Grill the steak for about 5-7 minutes on each side, or until desired doneness.
Remove the steak from the grill and let it rest for 5 minutes before slicing.
In a large bowl, combine mixed greens, cherry tomatoes, corn, gorgonzola cheese, and red onion.
Top the salad with sliced steak and drizzle with additional balsamic vinegar if desired.
Serve immediately and enjoy!