1/2 c. cider vinegar
2 tbsp. water
1/2 tsp. salt
3 tbsp. sugar
3 to 4 tbsp. fresh dill (or 1/2 dill and 1/2 parsley)
2 cucumbers, thinly sliced
1 thinly sliced onion (optional)

Mix all ingredients and refrigerate at least three hours.