How much daily salt does a chiuaua need ?

My neighbor's dog has been licking salt off my hands like crazy the last couple weeks. Does she have a salt or iodine deficiency ?

She probably does not have a deficiency but the only way to know for sure would be to have the vet run a quick and inexpensive blood test. Some dogs just like the taste. I have a Labrador that occasionally licks the salt block that we have out in the pasture for the cattle and deer. Her diet is adequate enough to be supplying all the salt she should need and her pre-operative bloodwork (for when she was spayed) showed no salt imbalances.