Place the marinade ingredients into a large ziplock baggie or a glass pan and stir them together. Add the steak to the marinade and turn it over to coat. Marinade the steak for at least 4 hours or overnight in the refrigerator, turning it often to coat all sides of the steak.

When you're ready to grill, remove the steak from the refrigerator and allow it to sit at room temperature for about 30 minutes. Soak the corn in a large bowl of water for 30 minutes. Preheat the grill to medium. Place the corn on the hot grill grates, grilling until the ears are slightly charred on all sides. Remove them from the grill and let them cool. Cut the corn kernels off of the cobs. In a large bowl, mix the corn, tomatoes, olive oil, vinegar and basil. Season with salt and pepper to taste.

Drain the steak from the marinade and grill, covered, until it has good grill marks, 5 to 6 minutes. Flip and cook, covered, until the steak is done to your liking, 4 to 5 minutes for medium rare. Transfer the steak to a cutting board and let it rest for 5 to 10 minutes. Thinly slice against the grain. Serve the sliced steak topped with the corn salsa.