Dried onions are handy for anything from soups to making hiking meals.  (which is why I am drying them)  As with most veggies there is very little prep work needed to dry onions.  You can slice them into rings and dry or into strips.  Just make sure that they are no thicker then 1/4 inch, and are not touching each other on the drying rack.  Dry at 130F for 6-8 hours.  When they are done they will be dry and brittle.  Unless you like to have watery eyes a lot you should always dry onions in a garage or in an extremely well ventilated room.  (same goes for spicy peppers) As soon as I get more veggies and herb dried I will start on making some trail cooking recipe posts.