Add 3/4 cup water to a large skillet, along with the juice of 1/2 lemon, 1/2 teaspoon salt and 1/8 teaspoon pepper. Add the shrimp in one layer and heat over medium/high.
When water starts to bubble, reduce to medium and slowly simmer about 2 minutes. When the shells are pink, flip each shrimp then cook another 2-3 minutes until firm/no longer opaque. Remove from heat and transfer shrimp to a paper towel-lined dish to cool.
When shrimp are easy to handle, remove/discard the shells and transfer to a mixing bowl.
Pour dressing over shrimp and stir gently to coat each piece. Allow to sit for a few minutes while you prepare the rolls.
Heat large skillet or grill pan to medium, then butter the insides of the rolls. Lay flat in the hot pan and watch them until they're nicely browned (1-2 minutes).
Add lettuce to each roll, then place about 6 shrimp in each (optional: sprinkle more lime juice over each) and serve immediately.