I also like the individual servings of tuna. Last time I took small zip lock baggies with pre measured minute rice. Boil water, dump the rice in and let it set for a couple minutes. I took the packets of individual slices of Spam and would dice it up and put it in with the rice. A little hot sauce and it was a pretty dang good meal.
A lot of the stuff you eat three days back in the mountains by yourself is bland. I take a zip lock baggie and fill it with individual packets of ketchup, mustard, texas pete, A-1 sauce, Soy sauce etc. I picked up all of them at various fast food spots.