Take off my skin - I won't cry, but you will! What am I?

Why this works

This riddle plays on the dual meanings of "skin" and the emotional response to cutting an onion. When you "take off the skin" of an onion, you're peeling away its outer layer. While the onion itself doesn't cry, the act of cutting it releases chemicals that can make you tear up. So, the riddle cleverly contrasts the physical action of peeling with the emotional reaction it provokes in humans!