Pare and slice 2 medium cucumbers. Sprinkle evenly with 2 teaspoons salt and set aside for an hour. Squeeze excess liquid from cucumber and combine them with 1 onion, sliced and separated into rings. Cover with a marinade of 3 tablespoons vinegar, 3 tablespoons water, 2 tablespoons sugar, 1/4 teaspoon paprika and 1/4 teaspoon black pepper. Sprinkle with paprika and refrigerate for a couple of hours.