Cut cucumber vertically in half. Slice thinly and diagonally. Sprinkle with a couple of pinches of salt and let sit for 5-10 minutes. Remove the moisture with a paper towel.

Scrape the meat of the Umeboshi from the pit with a knife and discard pits. Chop the meat finely to make a paste. Mix Umeboshi with Soy Sauce in a small bowl. Add the paste to sliced cucumber and mix.