I wipe my dogs down with a damp cloth sometimes to cool them off, they much prefer that to actually getting sprayed by water. There are also treats called "Ice pups" put out by the "Honest Kitchen", which does dehydrated raw food...just mix with water & freeze in ice cube trays...they LOVE these things! Here's a link so you can check them out...good luck!
Grain Free Dog Treat, Dog Ice Cream – The Honest Kitchen