Wear gloves if you prefer, then remove stems and roughly chop the Red Chilies; if you want milder heat, remove some or all of the seeds. Peel and roughly chop the Garlic.
Place the chopped chilies and garlic in a blender or food processor with the Rice Vinegar, White Sugar, Sea Salt and about 2–4 tablespoons of Water to help it come together. Start with less water — you can thin later.
Pulse or blend until you reach your desired texture: a coarse, rustic sauce or a smooth purée. Scrape down the sides as needed to ensure an even blend.
Pour the blended mixture into a small saucepan and bring to a gentle simmer over medium-low heat. Cook, stirring occasionally, for 5–10 minutes to marry the flavors and reduce any raw sharpness.
Taste and adjust: add more sugar to round the heat or more vinegar for brightness; add a pinch more salt if it needs lift. If the sauce is too thick, stir in a splash of water and warm through.
For a silky sauce, strain through a fine sieve into a bowl, pressing solids to extract as much flavor as possible; otherwise leave it as-is for more texture.
Let the sauce cool, then transfer to a sterilized jar or bottle and refrigerate. The sauce will keep for several weeks chilled; flavors deepen after a day or two.
