Wash and slice cucumbers into half-moons about 1/4-inch thick. If using regular cucumbers, halve lengthwise and scoop out seeds before slicing.
In a large bowl, combine sliced cucumbers, cottage cheese, shredded cheddar, and red onion.
In a small bowl, whisk together dill, apple cider vinegar, olive oil, salt, and pepper.
Pour dressing over salad and toss gently to combine.
Taste and adjust seasoning. Garnish with parsley if desired. Serve immediately or refrigerate for 30 minutes to let flavors meld.