Certain varieties of cucumbers have been bred specifically for use in pickling. By using these varieties, the home pickling enthusiast will end up with a crisper and more flavorful result.

Pickling cucumbers typically have thinner skins than the salad type, allowing for the vinegar, brine, or other pickling solution to better penetrate the skin and flavor the meat. They are short and squat, instead of long and lean. Pickling cucumbers also usually have “warts,” the little bumps on the skin that are the trademark of the classic dill pickle; salad cucumbers usually have much smoother skins. -wisegeek.org