1. Combine first 8 ingredients in a medium bowl. Cover and chill until ready to serve.
2. Heat a large nonstick skillet over medium heat. Lightly spray insides of buns with butter-flavored cooking spray, and place, sprayed sides down, in skillet. Cook 1 to 2 minutes or until golden brown.
3. Layer buns evenly with lettuce leaves, tomato slices, and lobster mixture.