Fry for several minutes in hot oil, until slices begin to turn golden (not too dark), and they are beginning to get tender. They do not need to be really soft at this point.
Take slices out of oil and drain on a paper towel.
Move to a sturdy surface like a cutting board, and smash the slices down with the bottom of a cup (like a juice glass or some such). The point is to make them smash down to about ½ their original height, not to get them really thin.
Throw back into hot oil and fry again, until they get more tender, maybe 1 – 2 minutes on each side.
Take out of oil, drain, sprinkle with salt and server in place of potatoes.