Sunomono (Japanese Cucumber Salad)

Steps

1. Put the wakame in a large bowl of cold water and let it soak for 5 to 10 minutes: it unfurls and swells to about ten times its volume.
2. Make the dressing: in a small bowl, mix the rice vinegar, sugar, and soy sauce, stirring for 1 to 2 minutes until the sugar is completely dissolved and you feel no grit under the spoon. Keep it in the fridge.
3. Wash the cucumber. If the skin is thick, peel it in alternating stripes for a nice striped look. Halve it lengthwise; if the seeds are large and watery, scoop them out with a small spoon. Slice it into half-moons as thin as you can, 1/16 inch (1 to 2 mm), with a mandoline or a very sharp knife.
4. Put the slices in a bowl, sprinkle with the fine salt, and toss with your hands. Let them sit for 10 minutes: the slices go limp and clear liquid collects at the bottom.
5. Meanwhile, slice the radishes into very thin rounds. Drain the wakame, squeeze it between your palms, and cut it into 3/4-inch (2 cm) pieces, removing any tough ribs. Break the crab meat into large chunks and pick out any bits of cartilage.
6. Grab the cucumber by handfuls and squeeze firmly over the sink until it barely drips: it should form a soft ball that falls apart on its own. Taste a slice; if it's too salty, rinse it for 5 seconds under cold water and squeeze again.
7. In a bowl, toss the cucumber, wakame, and radishes with three quarters of the dressing. Let it sit in the fridge for 5 minutes so the flavors sink in.
8. Crush the sesame seeds between your fingers over the salad to release their aroma. Arrange the sunomono in small mounds on an oval platter or in small bowls, set the crab on top, drizzle with the remaining dressing, and serve well chilled, within the hour.