Shaved Cucumber Salad

With a vegetable peeler, shave cucumbers into wide ribbons, stopping when you reach seeds; reserve 1 center. Thinly slice celery stalks and onion; place in a large bowl along with cucumber ribbons. In a blender, puree reserved cucumber center, mayonnaise, cilantro, and vinegar; season with salt and pepper and add to bowl. Toss to combine and top with celery leaves if desired.