Vinegared Cucumber

4 japanese cucumbers, or 2 western cucumbers peeled and seeded
1 c. rice vinegar
1 c. dashi
4 tbsp dark soy sauce
2 tbsp sugar

Cut cucumbers into paper-thin slices. Spread out on a cutting board, sprinkle with salt, knead about 1 minute. Transfer to bowl without washing.
Sanbaizu sauce: Combine sauce ingredients just to a simmer, force-cool (bowl in a bowl of ice water).
Serve: pour half the sauce over the cucumber, squeeze with your hands, pour off sauce. Then add the other half of the sauce to the cucumber. Serve at room temperature.
Note: you can add wakame too; soaked, scalded in hot water, plunged into cold water. Toss with cucumber just before adding sauce.

Source: Japanese Cooking, a Simple Art, by Shizuo Tsuji, p. 423