If you want to make cold wakame, you need to blanch it in addition to soaking it. If you don't blanch it, the wakame will have a fishy odor and taste bad, and blanching it will remove the fishy odor. It usually doesn't take too long to blanch it, about 2 minutes under boiling water will do.

Wakame is easy to scald. Clean it, cut it into pieces, soak it in water for 10 minutes, then stir-fry it in boiling water for 2 minutes, then take it out of the cold water to cool it down, and then stir in your favorite seasonings.