@wilma I’m not sure why anyone would pound salt, but maybe it is something that was done at one time. Perhaps it refers to crushing large pieces of salt into finer crystals, or weighing salt into smaller increments; both of which would be dull menial work. Maybe it refers to walking on salt, similar to ‘hit the bricks’ or ‘kick mud’, since salt is often spread on the ground as a de-icer in winter and is also common in desert and seashore areas.
(NSFW) It could also mean to got F yourself
@wilma passing the salted popcorn