Cut cucumbers in half lengthwise and scoop out seeds. Cut crosswise into 1/4 -inch-wide half rounds. Put cucumbers in a colander and sprinkle with salt. Toss with your hands to mix well. Let stand 2 hours. Rinse cucumbers, if desired. Gently squeeze water out of cucumbers and drain on paper towels. When well drained, return to colander.
In a large bowl, whisk sugar, vinegar, mustard and oil. Add cucumbers and mix with hands. Mix in onion. Cover and refrigerate 2 hours. Add dill and paprika. Mix well. Serves 6. Can be stored in refrigerator up to 1 week.
