Preheat the oven to 200ºC/gas mark 6. Toss the potatoes in a roasting tin with 1 tbsp oil, 1 sprig of rosemary and the lemon zest. Roast for 20 minutes. Meanwhile, mix the remaining rosemary and oil together with the cumin and garlic to make a marinade.
Heat a frying pan over a high heat. Add the duck, skin side down. Reduce the heat and fry for 6-8 minutes until crisp. Turn and cook for 5 minutes. Brush with the marinade, then remove and transfer to the tray in the oven. Roast with the potatoes for 10 minutes.
Meanwhile, pour the wine into the pan used to cook the duck and mix in the jelly. Simmer for 5 minutes. Cook the beans in a pan of boiling water for 3 minutes. Drain.
Slice the duck and serve drizzled with the red wine sauce and the veg on the side.