Doesn't need to be kimchi. The technique described can be used for pretty much any fried rice combo--best to let the rice dry out a bit but not necessary and that's not active time--which, given you have the ingredients (which could mostly be frozen) takes maybe 5 minutes.
I forget which of the cooking sites I got it from but the gist was that spreading out the rice on a baking sheet for a few hours was fine without fussing around with overnights in refrigerators. And, with a rice cooker, it's not a big deal to do the same thing a couple days later if you want to as opposed to saving your rice.
(Leftover fried rice microwaves pretty well too so it's a pretty good candidate for leftovers whether a full meal or a light lunch.)