There's a pair of asteroids directly outside my space station that I have fully salvaged at least six times now. When completely salvaged, they disappear from the navigation list like I would expect, and they stay gone until I reload (single player sandbox). On reload, they're back exactly as they were before salvaging. Oddly, if I destroy the blocks with antimatter cannons or missiles they stay destroyed forever.
Edit: Ships I salvage do NOT come back. So far, only asteroids exhibit this behavior. I haven't done enough serious planet salvaging to comment on it yet
Edit: Ships I salvage do NOT come back. So far, only asteroids exhibit this behavior. I haven't done enough serious planet salvaging to comment on it yet