Cut the hearts of palm into oblique chunks and add them to a large bowl.
Mince the celery and add to the bowl with the hearts of palm.
Add the dill, chives, Old Bay seasoning, salt, pepper, lemon juice, and mayonnaise and stir to combine.
Brush the insides of the potato buns with the melted butter.
Toast in a medium skillet over low heat for 2-3 minutes, until golden.
Fill the buns with the hearts of palm mixture.
Garnish with chives.