This is more of a marination than a pickling.
In a clean stoneware crock or 1-gallon glass jar, combine equal amounts of cider vinegar and water to half-fill the container. (Use bottled water if your tap water is chlorinated.) If desired, measure the total liquid in order to calculate the salt. Add the dill heads, garlic cloves, salt, bay leaves, peppercorns, and mustard seeds. Stir. Toss in the vegetables and set the crock aside, uncovered. Every day, eat the vegetables that you added the day before, then add more. (The vegetables should not be in the crock for more than 2 days.) Empty and clean the crock after 2 weeks and begin again.
Experiment with flavored vinegars and different fresh and dried herbs and spices.