Prepare the dried seaweed by soaking for 10 to 20 minutes and rinsing well. Boil water in a small pot, and add 1 teaspoon of salt. Blanch the soaked seaweed briefly. Drain and rinse with cold water.
In a medium size bowl, gently toss the vegetables with the seasoning ingredients. Set aside for about 10 minutes. You can make ahead up to this point several hours or a day before, if desired.
Mix in 4 cups of cold water and season with salt. Start with a half teaspoon of salt, taste and add more if necessary. Refrigerate to chill. Serve in chilled bowls with some ice cubes.