Wash and rub the cornicons to remove the prickles. Then put them in a strainer, sprinkle heavily with pickling salt (or any salt without iodine added), and leave them overnight. A good amount of juice will drain from the cucumbers.
The next day, rub off the excess salt (rinsing is not needed since a little remaining salt is desired). Then wash jars with tight-fitting lids and pack with the cornichons along with:
One or two peeled garlic cloves
Several whole peppercorns
A few sprigs fresh thyme and tarragon
A bay leaf
A little lemon juice (or slice of fresh lemon)
Then fill the jar with white vinegar. The pickles will swell as they absorb the vinegar, so make sure they are covered with a little space to spare. Place the lids on tightly and leave them at least a couple weeks for the cucumbers to absorb the flavors. That's it. Spicy and delicious.