Heat the oven to 200°C (180°C fan) 400F, gas 6.
Mix the yogurt, vinegar and sesame oil.
Stir in the garlic, ginger, coriander, cumin, chili, turmeric and some pepper.
Brush the meat with the marinade, cover and chill for at least 6 hours.
Reserve excess marinade.
Place the marinated duck in an oven proof dish covered with tin foil and cook in the middle of the hot oven for 20-25 minutes.
Brush occasionally with the remaining marinade.
Serve the tandoori duck on plates with the cucumber, ginger and lemon slices.