How do I get seasoning to stick to home-popped popcorn?
If you want dry seasonings to stick to popcorn, you will probably need to add a liquid to adhere them with. You could try adding butter or oil to your popcorn while it is hot, then adding the salt and tossing it together. If you're avoiding extra fat, a few spritzes of a non-stick spray (like Pam) might do the trick without adding significant fat.