Removal of a low-slack chain.

Push as hard as you need, laterally, with your foot, against the mid point of the chain. Then roll the chain. You only need to pop the chain out of alignment of one or two teeth and it'll start to drop off.

 

I've done this before when the chain has been *very* tight (after dropping a link) and haven't noticeably deformed the chain or chainring teeth.

Done