Preheat your grill or grill pan over medium-high heat. Rub the flank steak with olive oil, salt, and black pepper.
Grill the steak for about 4-5 minutes on each side for medium-rare, or until it reaches your desired doneness. Remove from the grill and let it rest for 5 minutes before slicing.
While the steak is resting, grill the corn kernels in a grill basket or on skewers for about 5-7 minutes until charred, stirring occasionally. If using frozen corn, thaw it first.
In a large bowl, combine the mixed salad greens, cherry tomatoes, grilled corn, and red onion.
Slice the rested steak against the grain into thin strips and add it to the salad.
Drizzle the balsamic vinaigrette over the salad and toss gently to combine.
Top with crumbled Gorgonzola cheese before serving.