Rice doesn't need all that water you see in rice patties to grow. Its just a weed control technique - rice grows fine submerged and weeds don't. It can be grown in dry fields - or the space station - too, and weeds aren't really a problem in space.

Flying wings are highly unstable, which (assuming you can control it with a flight computer) is a great feature in a military aircraft that might need to make sharp and sudden changes to it's flight path. It's not a great feature in a civilian aircraft where safety is #1 priority.