Cucumbers are not worth it. Go with zucchini. I scrub it with vinegar, slice it thick and rubberband it to a rock. You can also push a never-seen-soap solid stainless fork through it, but that gives me visions of impaled eyes, so I avoid it. There's also a device called the 'screwcumber' which is really a waste of money unless you just want to support the product.
Also, cut out the seeds. I've found nothing that eats them and they just float around and rot. So you end up with an 'O' shaped green slice on a small piece of slate held by a rubberband, not too tightly or the veg will drop in half once it's waterlogged.
What are you feeding? Some like it blanched while others, like most plecos and snails, take it hard and raw.