Pick Cornichon Pickling Cucumbers when 2" long (the width of a child's finger) and rinse lightly. Rub the skins with a kitchen towel. Sterilize glass jars according to the manufacturer's directions. Pack as many of the little Cornichon cucumbers as you can into each jar along with: 15 to 20 tiny, peeled silver-skinned onions; a hot pepper (or part thereof), a few peppercorns, fresh tarragon and one tablespoon of kosher salt. Fill each jar with white wine vinegar. Your prized, tart little cornichons will be ready in about one week and will last for months in the fridge. Perfect with pate de campagne, baguette and a glass of wine for a hot summer day's picnic dinner.