Quickly rinse the hijiki under cold water to remove any foreign matter, then soak in warm water for 10 minutes. Drain and dry with kitchen paper.
Soak the julienned vegetables in cold water for 5 minutes, drain and pat dry.
Mince the anchovy and mix with the other ingredients for the dressing.
Mix the hijiki and vegetables in a serving bowl. Pour the dressing on top, then serve.