Remove the lobster meat from the tail, knuckles and claws, keeping the meat intact. Split the tail down the center and clean the waste track.
Heat the water and 2 tablespoons of the lemon juice over medium heat in a medium saucepan. Whisk in the cold butter cubes a little at a time, being careful to make sure it forms a creamy emulsion. Rotate the saucepan off and on the heat, melting the butter until it is all incorporated. Season with salt and pepper. Keep warm but not simmering; the butter must stay emulsified.
Brush the hot dog buns with some room temperature butter on all sides. Toast in a large, dry skillet over medium heat, about 1 minute per side.
Add the lobster meat to the butter bath and warm through until fully cooked and the tails just start to curl, about 4 minutes.
Place the Bibb lettuce in a small bowl and dress with the olive oil and remaining 1 teaspoon lemon juice.
Fill the rolls with the butter poached lobster and drizzle with the Spicy Mustard Mayonnaise; the lobster roll should be warm. Finish with the chives. Serve each lobster roll with 2 of the lemon wedges. Plate the dressed lettuce on the side.
Spicy Mustard Mayonnaise:
Yield: 1 cup.
Whisk together the mustard powder, water, lemon juice, Dijon mustard and mayonnaise in a small bowl. Season with salt and pepper.