Shima tougarashi 島唐辛子 are island peppers, similar to small thai chilis. These type of small red peppers are also common in Hawai’i.
While Hawaiians make chili water, Okinawans make koregusu コーレーグース. The difference is Okinawans put the chilis in Awamori 泡盛. Yup, that’s the recipe, just add some small red chilis to cheap awamori, let it “age” a bit, and you have Okinawa’s equivalent of hot sauce. I read someone use a ratio of 20 peppers to 200mL of awamori, but my husband says that is not really enough and to just add as much as you like. Suffice to say, it is simple to make at home (check out the “recipe” in my recipes section). Sometimes I buy bottles from little obaasans that bottle their own in the farmers markets or alongside the road.
If you like this, you may consider also trying hiruzaki ヒルザキ, made from island garlic and awamori.