4 Tbsp white sesame seeds
1 Tbsp soy sauce
1 Tbsp rice vinegar
1 tsp sugar
1 lb fresh or frozen green beans, cooked and cooled
Pour the sesame seeds into a dry frying pan and roast over high heat until they start to pop, turn color, and give off a nutty aroma, 3-5 minutes. Allow to cool, then put the sesame seeds in a mortar and grind them with the pestle. Push hard! When the seeds resemble a rough paste, transfer them to a small mixing bowl or cup. It's fine if there are some whole seeds left.
Stir in the soy sauce, rice vinegar, and sugar, and mix well. Toss the sauce with the green beans and serve right away.