To reduce saltiness in over-salted pickles, rinse them thoroughly under cold water or soak them in water or a vinegar-water solution for a few hours.
Overly salty pickles can be unappetizing, but thankfully, there are several ways to mitigate the saltiness. The most straightforward method is to rinse the pickles under cold, running water. This physically washes away some of the excess salt clinging to the surface. For a more significant reduction in salt, soak the pickles in a bowl of cold water. The water will draw out the salt through osmosis. Change the water every hour or so for best results. Another effective technique involves soaking the pickles in a solution of water and vinegar (a 1:1 ratio works well). The vinegar helps to balance the flavors and counteract the saltiness. The soaking time will depend on how salty the pickles are, but start with a few hours and taste-test periodically.
If you're making your own pickles, use a salt calculator or recipe that specifies the correct amount of salt based on the weight of your vegetables and brine. Too much salt not only affects the taste but can also inhibit proper fermentation.