• Mix the sauce ingredients in a small saucepan and bring to a boil over medium high heat, stirring frequently.
• Reduce the heat and continue to stir while the sauce reduces and thickens.
• The sauce is ready when it coats the spoon, but still runs freely.

For the string beans

• Thinly cover the bottom of a large skillet or stir fry pan with oil. Add a pinch of red pepper flakes.
• Heat over high heat until very hot, then add the green beans. There will be a lot of hissing and popping, but keep moving the string beans around.
• Continue to cook for several minutes until the string beans are crisp tender.
• Stir in a quarter cup or more of the stir fry sauce and a couple tablespoons of sesame seeds. Toss to coat.