Most of the time the Japanese kids and adults are at school, work and restaurants for lunch. The housewife, for herself, will usually eat her lunch rice with last night's supper leftovers. Often she will combine all of it into one rice bowl, a simple dish called domburi. In another version of this one-meal bowl, either green tea or soup broth is poured over the rice for a wet dish called chazuke. Favorite toppings for this include sashimi (raw fish), salted fish, nori (dried seaweed), omelet and/or pickle. The tea or broth (dashi) is poured over and let soak for a few minutes. The meal is eaten with chopsticks.
If you have mostly rice and few leftovers, the Japanese have some bottled mixed seasonings made just to sprinkle on and flavor plain rice. These are called furikake and varieties can be found at your asian market.
Again, some kind of soup (miso or clear) will probably be found at most Japanese lunches.