The skin on the flat surface of the clove will split under the pressure. You can then slip your finger into the split and quickly tug off the skin.
The advantage of this technique (besides feeling like a super hero who can crush rocks bare-handed) is that the garlic clove itself remains unbruised. This is something that's hard to avoid when you're smashing the clove with the flat of your knife. Normally this isn't an issue since we end up mincing the garlic anyway, but there are certain dish presentations where whole, unmarred cloves would be a plus.
Plus, no knife or other potentially wound-inducing kitchen implement needs to be used for this technique. If that has been a source of worry for you, this is a dream come true!
We have to admit that some of the larger cloves or cloves with particularly thick skins give us some trouble with this technique. We also couldn't see peeling more than a few cloves this way and will probably fall back on our old smashing method for a dish that requires a lot of garlic.
Give it a try next time you need a few cloves!
Related: Recipe: DIY Garlic Paste
(Images: Emma Christensen for the Kitchn)