You could just skin and salt, BUT they will end up being very dry, hard, and unplyable and probably won't last long.
To sell you need to skin, including stripping the tail, sew the bullet hole/s, flesh and stretch. Once that is all done, they can hang dry until you get them sold.
Personnally, I freeze all mine whole, and sale them in the round when I get a chance to get to a buyer. Let them skin them. IF I had a skinning shed, I'd skin them, but I don't, yet. Some guys skin them in the field too, which isn't a bad way to go, if you have a skinning pole and want to take the time to do it.