Preheat the oven to 200ºC/fan 180ºC/gas mark 6 and place a baking tray in the oven to warm. Cook 3 duck breasts in a large non-stick frying pan, skin side down, over a medium heat for 5 minutes until crisp. Turn over and cook for a further 2 minutes. Remove, cover with foil and set aside while you pan-fry the remaining duck breasts.
Transfer all 6 duck breasts to the warmed baking tray and cook in the oven for 15 minutes. Leave to rest for 5-10 minutes before slicing. Meanwhile, put the orange slices into the pan with the remaining duck fat. Cook for 2 minutes each side until golden, then set aside. Toss together the salad leaves, beetroot and orange slices.
Mix together the soy sauce, honey, olive oil, garlic and balsalmic. Serve the duck with the salad and drizzle over the dressing.