1. Cut the cucumbers in half lengthwise. Peel them and remove the seeds. Slice the cucumbers thinly and sprinkle with salt. Set aside for 10 minutes.
2. Rinse the cucumbers and squeeze out any excess water. Add the shrimp to the cucumbers.
3. Soak the wakame in water to cover for 5 minutes. Cut or tear the soft portion of wakame from the core into 1-inch lengths.
4. Combine the cucumbers, shrimp, and wakame. Mix together the sugar, 1/2 teaspoon salt, and the vinegar. Pour over cucumber mixture and chill in refrigerator for 1 hour or longer.