We love to dress up steamed asparagus or broccoli with this sauce. When tangerines are in season, squeeze them fresh for an especially interesting variation.
Heat oil in a small saucepan over low heat. Add sesame seeds and stir until lightly toasted, about 20 seconds. Add shallots and stir until softened, about 1 minute. Add zest and juice, vinegar and soy sauce. Simmer until reduced to 1/2 cup, about 6 minutes. Stir in chives (or scallion greens).
People with celiac disease or gluten-sensitivity should use soy sauces that are labeled "gluten-free," as soy sauce may contain wheat or other gluten-containing sweeteners and flavors.