Put about 2 inches of water in a large pot; salt it, then cover and bring to a boil. Plunge the lobsters into the boiling water. Cover and cook about 10 minutes or until the lobsters are bright red. Plunge into a bowl of ice water until cool enough to handle. Remove all the meat; shred with your hands or roughly chop it. Work quickly so meat stays warm.
Split and lightly toast the buns. Divide the lobster meat among the 4 buns, spoon 2 tablespoons melted butter over each sandwich and sprinkle with salt. Makes 4 servings.