Bless your little birdie heart. You can't punch people in the face, you have no hands to make a fist.

I have an alternative though. Remember your love rock? You need a rock launcher designed for penguin use. Yeah. It'll kinda be like a crossbow, but with a sling shot like pouch on the back end that holds rocks. Also, an easy press button you can peck at. Aim straight for the groin. Much better than punching people in the face.

Bonus? Because your ammunition is your love Rock, it will always come back to you cause that's what true love does.