In a medium bowl, mix the lobster, mayonnaise, celery, onion, lemon zest and 1/8 tsp. pepper.
Heat a large nonstick skillet over medium. Spread the inside and outside of the buns with the butter. Open the rolls and place two of them, split sides down, in the skillet. Cook until lightly browned, turning once, 3 to 6 minutes. Repeat with the remaining rolls.
Divide the lobster mixture among the buns. Serve with the lemon wedges.