Mix 2 parts water to 1 part white vinegar and wipe the salt stains down ASAP. Then wipe down with a damp rag and let them dry naturally do not place near a heat source to dry. I too doubt they are ruined.
Several thin coats of paste wax will protect your shoes in the winter very well. Cream or cream polish, not so much. I always wax my shoes and boots a couple of extra times in the fall before the snow falls and also during the winter. Check your soles every day when you get home and make sure you don't have chunks of salt stuck in the leather soles too.