Sorry, more accurately salt and snow melt chemically lowers the melting temperature of water and so the liquid water a dog's paws encounter can be much lower than 32deg F. If a snow/ice/salt solution is frozen, it is likely significantly colder than 32deg F. Direct contact with salt is indeed irritating and can dry out and chemically burn paw pads, but contact with salt won't just "super cool" them. It's the contact with colder than freezing water due to salt that is dangerous.