Lay the cucumber on a chopping board and smack it hard a few times with the flat blade of a Chinese cleaver or with a rolling pin. Then cut it, lengthways, into four pieces. Hold your knife at an angle to the chopping board and cut the cucumber on the diagonal into ?–? in (½–1cm) slices. Place in a bowl with the salt, mix well and set aside for about 10 minutes.
Combine all the other ingredients in a small bowl.
Drain the cucumber, pour over the sauce, stir well and serve immediately.