One of the first fruits that I dehydrated was some organic, seedless navel oranges. Preparation was easy. I simply soaked the oranges in a water / vinegar / salt solution for about 15 minutes, rinsed them well and sliced them with my mandoline slicer approximately 1/4 inch thick.
Lemons and Limes can be dehydrated using this same method.
Do you dehydrate any foods? What is your favorite?