You can make super simple pickles from extra cukes, using the brine from your favorite store bought pickles.
After you have finished the jar of pickles, don't throw the jar...or the brine....away. Simply slice up your fresh cukes and drop into the brine. Stir with spoon to be sure that slices are covered. Let sit for a few weeks in the fridge and then enjoy!
(I actually will only re-use the brine once, maybe twice, then throw away.)