Yes, you can dry cooked beans. They will rehydrate again in about 10 minutes in boiling water. I've dried refrieds in my dehydrator before to make a rough mealy powder that rehydrates suitably enough to add to soups or stews (it does not rehydrate back into refrieds quite so good.

If you don't cook them to the point where they break down, they should rehydrate into a nice chili bean stew addition (what Yankees call Chili).