Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Wash duck breasts, dab dry. Cut the skin crosswise. Season with salt and pepper. Heat a pan without fat.
Roast duck breasts first on the skin side for approx. 2 minutes, then turn and roast for approx. 1 minute on the meat side. Drizzle with 8 tablespoons of Teriyaki sauce, allow to draw briefly and roast in a hot oven for 10-12 minutes.
Clean and wash the beans. Peel the garlic and cut into wafer-thin slices. Bring sesame oil, butter, 75 ml water and 1 tablespoon teriyaki sauce to the boil. Cover the beans and garlic and cook for about 8 minutes until the liquid has evaporated.
Season beans with lemon juice and pepper. Cut the duck breasts into slices and drizzle gravy over them. Serve with beans. Sprinkle with sesame seeds. Serve with rice.