you pinch and twist between each set of leaves. you continue to do it in the same area (between the same leaf sets) as much as possible waiting until the plant has recovered before doing it again. you won't be able to do it more than 2, maybe 3, times before the stem is too thick to pinch.
Personally I just pinch in the same spot from 2 or 3 directions versus twisting.
The purpose is to shorten the node length and give the stem extra strength; both of which should help the plant be self supporting and more compact. you'll still need to stake the plants however if they have large fruits. They do keep the plant considerably smaller however which is nice on an elevated growing surface.
I personally would not supercrop between the crown and first leaf set. Wait to do it between the 1st and 2nd node.That way if you twist off the top, you just wait for a sucker to develop and continue from there.
As for other plants, I imagine any plant you wanted to grow more compactly would work. maybe not plants with woody stems as much, but that's purely speculation.