The other day, I made the Salty Margarita Sour from Joe Yonan's Cool Beans.
He credits the idea to a margarita he had at José Andrés's Mexican restaurant, Oyamel, topped with a foamy layer of "salt air" instead of a salt rim on the glass. Yonan decided to try it with a frothy layer of whipped, salted aquafaba. I don't really care for the grittiness of salt rims on cocktails but I enjoyed this version.
The recipe is available online at this link. Scroll down, it's the last recipe.