There are people who have spent thousands of years farming in environments as arid and hot as Saudi Arabia. What's out there isn't as well-marketed as permaculture, but it's also a lot less woo-woo and proven to be sustainable. In my area (California), I've found dryland techniques from Arizona natives to work extremely well. Considering Arizona is around the same climate as Saudi Arabia, but with more rivers, I suspect they'd probably work there too. Nabhan's Enduring Seeds captures the general principles decently, but the technical information is scattered about in various places. You may have even more luck with things like Sorghum (a highly drought-tolerant African crop) in a more local system.