Peel and thinly slice a 4-inch piece of ginger; put in a small jar. Pierce 1 or 2 Thai chiles with the tip of a knife; add to the jar. Bring 1/2 cup each rice vinegar and water, 2 tablespoons sugar, 1 teaspoon kosher salt and 2 star anise pods to a simmer in a saucepan; cook 5 minutes, then pour over the ginger and let cool slightly. Cover and refrigerate overnight or up to 2 weeks.
Photograph by Kang Kim