This isn’t really much of a recipe, but I think it deserves mention anyway. Everytime I have this dish, it takes me back to the hot muggy summers in Kesennuma when all of the hotels opened up roof-top beer gardens and served simple grilled dishes and beer. These beer gardens would be denoted by bright red lanterns, but before even approaching, the first signs of the beer garden would be the laughter and music streaming down. My favorite beer garden would serve chilled spears of cucumber with miso and vinegar or occasionally a small dish of Shoyu Koji. This in my mind is the perfect match to a frosty mug of beer.
Although these cucumbers are great with miso and vinegar, the miso can be a bit salty. If you do decide to go that route, buy a good quality organic miso. I prefer the red or brown miso (Sendai style) which tend to be a bit more robust than the yellow or white misos that you will occasionally see. Add just a few drops of rice vinegar to thin out the miso and add some acidity.
Although it can be difficult to find, Shoyu koji, the pre-cursor of soy sauce, is a bit sweeter and is my favorite. Shoyu koji is actually a mix of fire roasted grains, soy beans, salt, spring water, and koji culture which is the starter for kicking off the fermentation of soy sauce. Look for it in the refrigerated section of your local Asian market. It is often hidden between tubs of miso and Japanese pickled vegetables (tsukemono).