what is/are cornichon?

Cornichons are also quite delish on cheeseburger for an extra tangy pickle

baby pickled cucumbers, also known as gherkins..

They're also a part of the traditional (French) Tartar Sauce.

They are also good chopped up in olive salad.

A cornichon is a teensy (about the size of your pinky) sour pickle usually served to accompany pate.