This one i've tried it works really well. I got the info on it from Backpacking magazine. This is for a backpacking trip, but worked really well for daytrips of camp outs with lots of events, and minimal time for lunch. What you do is take a clear plastic dish and mix the proper amount of water and rice acourding to the box(i found instant rice worked better), and store in your bag or at camp 8 hours later its ready to eat. It's really good with prepackaged italian dressing.
I know this was a question to make rice with out utensils, but i thought it might fit by not using fire.
DGL