If you grow pitaya plants yourself, and you have managed to succeed in growing fresh dragon fruit on the plants, you might want to try drying dragon fruit yourself so you can have you own dried dragon fruit supply even when the season for the fresh pitaya fruit is over. When you are drying pitahaya fruit yourself, you can either peel of all of the skin, or leave it on. When drying dragon fruit, first slice it across the long axis of the fresh fruit. Slices 2-3 mm (about 1/4 of an inch) thick work pretty well for drying dragon fruit. Once the fruit is dry, you won't notice all that much whether you left the skin on or removed it before drying. It kind of blends into the dried dragon fruit you get at the end of the process.
Drying pitaya fruit is a great excuse to save any blemished fruits or fruits that you can't eat for any reason, but which are ripe. If you grow pitahaya fruits such that you all of a sudden have too many to eat all at once, don't toss your fresh pitahaya fruits into the rubbish bin if they are too ripe to eat - dry them instead! As long as they aren't spoiled, they should be fine for drying.
Drying dragon fruit isn't all that complicated. You can sun dry them on a screen (having a low humidity series of days helps here), hasten drying in an oven at a low or warm setting (like 200 degrees F - NOT a temperature to cook them), or let them dry in a super low humidity environment. Drying pitaya fruit this way will give you a dried pitaya fruit result which is textured and more robust to eat. If you have access to a real freeze dryer, then after drying dragon fruit you'll have a more 'freeze dried' texture which is crunchier instead of chewy. True freeze drying dragon fruit will give you a dried fruit which will last longer, but remember that you can refrigerate or freeze the 'air dried' or 'sun dried' dragon fruits very effectively to keep them for a long time without full bore freeze drying.
Because growing pitaya cactus plants all the way to fruiting can be complicated, and you may at times miss all or some a flowering (e.g. if pollination fails for a given pitaya flowering night), having as a backup dried pitaya fruit is good way to extend your pitaya growing season for those times when fruiting is poor.