Remove stems from shiitake, discard stems, reserve soaking water and slice the caps thin. Place the water, shiitake soaking water, kombu and shiitake in a soup pot. Cover and bring to a boil. Reduce the flame to medium-low and simmer 5 minutes. Remove kombu and set aside to use in another dish. Add the grated daikon and sea salt. Cover and simmer for another 10 minutes. Garnish with nori and scallions before serving.
Per serving - 30 calories, 0 g fat (8% calories from fat), 1 g protein, 6 g carbohydrate, 4 g fiber, 0 mg cholesterol, 297 mg sodium