One of the things that I have done with leftover zucchini is to make sweet relish with it. It works just as well as cucumber does, tastes about the same, and will keep well. Then, you have plenty of relish for sandwiches all winter long.
When I run out of ways to use tomatoes, or just plain get tired of eating them, I get out the dehydrator and dry them. I slice them thin, add salt and pepper, and lay them on the dehydrator racks to dry. They work perfectly in any recipe that calls for either fresh, canned or sun dried tomatoes, and are so delicious, you can eat some for a snack.