Although I have posted this before, I decided to post it again with more details and a better picture. I make this regularly with whatever vegetables are available but cucumber, daikon, nappa cabbage, and celery are the best. I always use thinly sliced and Julienned ginger, red pepper flakes. From time to time, I add different seasonings such as jalapeno pepper, sliced lime or lemon. This time I had thinly cut dried kelp "Kizami konbu" 刻み昆布 (came in a bag) and I used this as well.
Then I transferred the vegetables to the contraption on the left called a Japanese pickling pot. I put on the lid and screwed down the inner plate so that the vegetables were under some pressure. I placed the pickling pot in the refrigerator. After several hours, you will see water developing above the vegetables. Then, it is ready. If you do not add enough salt, the water may never appear. (This is called "Mizu ga agaru" or "Water has risen"). After this, I transfer the vegetables in a sealable container with its liquid. I drain and squeeze out excess liquid just before serving.
Depending on the saltiness, you could use soy sauce when serving "asazuke". You could try many variations. Depending on the amount of the salt, it will keep at least a week in the refrigerator. We really like this dish. This dish can be served as a small dish which goes well with a sake. You could also serve this as an accompaniment to the rice dish you may serve as a "shime" 締め dish.