Soak wakame in a bowl of water for 10 minutes.
Peel cucumber and score down the outside of the cucumber with a fork. Slice cucumber very thinly into rounds.
Remove wakame from soaking water and slice into very small pieces. Place wakame pieces and cucumber rounds into a bowl. Pour over brown rice vinegar, umeboshi vinegar and let stand for 30 minutes. Serve 1-2 teaspoons with the meal.