There are a lot of highly drought tolerant species I’m hoping to gradually domesticate over time. Basically, if you go to this website:
. . . and search for “dry” as the soil type, and then go through every search result to see if it’s edible and choose all the ones that look quite likely to be delicious to my palate, and order them all . . . you will be doing exactly what I did! 
I’m hoping to turn my lawn into a prairie full of edible plants that don’t need to be watered in summer, and I’m hoping to turn my front yard into a beautiful xeriscape full of edible ornamentals that are super drought tolerant. Ideally, I would like to water both of those areas never, and yet harvest good food from them.
Since I imagine you’re curious about which plants I actually did select from them:
I also bought seeds for these three aquatic plants, because they sound tasty:
It’s very unlikely I could get them to grow in my dry desert sand, but I have a sneaky plan. Aquatic plants don’t mind wet feet – in fact, they love it – so why not bury some big plastic containers with no drainage holes, fill them up with wood chips and soil, and sow seeds of aquatic species on top? Betcha I can get away with watering them only once a week, since the water will never drain away from the bottom.