Grilled Lobster Sandwich with Charred Corn and Avocado Salsa

Name: Grilled Lobster Sandwich with Charred Corn and Avocado Salsa
Ingredients: 4 par-cooked lobster tails; Canola oil; Salt and freshly ground black pepper; Charred Corn and Avocado Salsa, recipe follows; 4 soft, sesame-topped hamburger buns, toasted; 1 red onion, peeled and sliced into 1/4-inch-thick slices; 1 to 2 limes; 1/2 cup mayonnaise, optional; 8 ears corn; 1 tablespoon kosher salt; 1/2 cup creme fraiche; 1/4 cup chopped fresh cilantro; 3 ripe avocados, peeled, pitted and diced; Juice of 2 limes; 1 serrano chile, grilled, unpeeled and thinly sliced; 1/2 small red onion, finely diced; Few dashes hot sauce, such as Tabasco; Salt and freshly ground pepper