Roast the pimento and all peppercorns in a pan without fat at medium heat for 1-2 minutes. Coarsely crush the spices and sea salt in a mortar.
Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Wash duck breasts, dab dry and cut the skin crosswise. Rub in with the spice mix. Heat an ovenproof pan without fat.
Sear the duck breasts over medium heat. This is how the skin gets crispy: first fry the skin side for 2 minutes. Turn, briefly roast the meat side, then finish cooking in the oven with the skin facing upwards for about 10 minutes.
In the meantime peel the ginger and dice it finely. Cut the chilli lengthwise, remove the seeds, wash and cut into rings. Clean and wash spring onions and cut into rings. Remove the outer leaves of the pak choi if necessary.
Wash the pak choi and cut into quarters lengthwise. Cut off the pineapple ends. Peel the pineapple and cut into pieces. Wash coriander, shake dry and chop coarsely together with the tender stalks.
Heat the oil in a frying pan. Fry the ginger, chilli and spring onions in it. Steam the pineapple for 2 minutes. Sprinkle with sugar. Add lime juice and Pak Choi and season with salt and pepper. Cover and stew for 4-5 minutes.
Heat the Teriyaki sauce. Cut the duck breasts open, arrange them and drizzle with the sauce. Serve with the vegetables.