Becky,
Good luck on your future oasis

. I have somewhat of an experience with drought and desert like conditions, in inland orange county. From my experiences focus on creating an edible drought tolerant plant list. I would start with looking at cactus and rely heavily for them on edible harvests. There is also a decent amount of perennial vegetables that would be relatively drought and heat tolerant.
Here is a small list off the top of my head (some of these were mentioned earlier in the thread).
Peruvian Cactus Apple (Cereus repandus); fruit
Prickly Pear (Opuntia *); fruit, pads, seeds (Would focus heavily on this)
Cereus fernambucensis; fruit, stalks (natives skin and boil)
Aloe Vera; stalks (good plant to have for medicinal and edible uses)
Wolfberry (Lycium barbarum); fruits, leaves (leaves make an excellent salad green that is very tasty and nutritious)
Perennial Tree Kale (Brassica oleracea); leaves (will grow into a small tree, plant in part shade)
Jujube (Ziziphus zizyphu) fruit (tasty fruit on a very drought tolerant plant)
Moringa oleifera; leaves, pods, flowers
There are many more plants to add, if your interested I can try to dig through my lists. All the ones listed above I grow, so have a little first hand experience with sun and heat tolerance.