I don't see why you couldn't put used salt water through a distiller
and reclaim almost all of it.

Why would you want to do this? What are the benefits?

I have not done this myself, but it ought to work fine. You can get small
countertop distillers from
Amazon for US$99 - US$200 that do a gallon at a time in four or five
hours. The question is whether it is worth the effort you'd put into
running a gallon at a time through the thing plus the cost of
electricity to run the thing.

Doubtful.

You'd probably want to clean the salt
and minerals left behind out between every gallon, too.

How would you 'clean' the salt and minerals?

I'm curious now and maybe I'll go ahead and take some of the water from
my next change and put it through the distiller and see what I get.

What is the advantage of distilling your water from a water change versus
water from the tap? You will NOT be able to separate the crap from your
salt and minerals for reuse.

Lastly, why are you doing water changes to begin with? I don't do water
changes and my fish, inverts and live rock are doing fine.