Remember how I suggested you make some extra of the 4-ingredient meal? You can, of course, reheat in a microwave.
But how about making something different? If you have a stove, you can make a frittata (an Italian egg dish): mix up a few eggs (2-4, say). Heat some oil in a non-stick pan. Mix your leftover rice concoction into the beaten eggs. Pour into your pan and turn the heat to low. Cook till cooked through. You might want to put a cover on the pan so the top gets cooked. It is quite a trick to flip the frittata.
Oh no! You are a dorm cook and only have your rice cooker. What to do? Well, it won't be as pretty, but you can scramble the mixture in your rice cooker. You may have to keep flipping the switch to cook.
Note that you have hardly made any mess at all. The first meal required only 1 pot or a rice cooker. No chopping. Second day: you have to mix up the eggs.
Save a little for tomorrow!