First, make the salsa by adding tomato, yellow onion, cut corn, cumin, cilantro, garlic, lime juice, and salt to taste in a medium size mixing bowl. Stir together and set aside. Once the salsa is done, preheat sauté pan on medium heat until hot. Add 2 tbs. of olive oil to the pan, next gently lay tuna steak in the center of the pan and brown each side until tuna is medium. Once tuna is medium, place the steaks on a baking sheet. Next, add 2 tbs. salsa on top of the yellow fin tuna. Top the tuna with mozzarella cheese and 2 tbs. of crushed tortilla chips. Place in a preheated 400-degree oven and bake until cheese has slightly browned. Serve tuna in center of warm tortilla chips and drizzle salsa around dish.