Cook Lobster(s) according to your preference. Be sure to allow to cool enough to handle when removing lobster meat.
Chop or tear into large chunks and set aside.
In a large bowl, mix the celery, mayonnaise, chives, lemon juice, lemon zest, kosher salt [and ground black pepper]. Taste for seasoning.
In a large skillet over medium heat, melt 2 tablespoons of the butter and add the lobster meat. Cook, stirring for 2 minutes until warmed through and buttery all over.
Use a slotted spoon to dish the lobster meat into the mayonnaise mixture and toss to coat. Discard butter and juice released from the lobster and wipe out the skillet.
Melt the remaining butter in the skillet over medium heat; toast the buns on the cut sides about 2 minutes each side until golden and toasty.
Melt the remaining butter in the skillet over medium heat; toast the buns on the cut sides about 2 minutes each side until golden and toasty.