Rinse duck under cold water inside and out then dry with paper towels. Rub inside and outside with salt and pepper.
Heat oil in a frying pan and saute onions until soft and translucent. Add mango chutney, coconut, curry, cayenne pepper and lemongrass; saute for an additional 1-2 minutes. Add cooked rice to the frying pan. Stir well.
Stuff duck loosely with filling and sew up opening with string. Tie legs and wings to the body.
Place duck breast side up into a roasting tin and roast on the lowest oven shelf for 1 hour and 45 minutes.
Pierce duck and prick from time to time at various places to drain the fat. At regular intervals deglaze brown bits with wine.
When duck is cooked through and the skin is crispy place on a serving plate then cover with foil and let rest.
Loosen drippings with water and pour through a strainer. Skim off fat. If the sauce is too liquid mix a little cornflour with cold water until smooth and add to sauce. Bring to the boil while whisking constantly until the sauce thickens. Season with salt and pepper.
Remove kitchen string and cut duck in the middle of the chest to remove the stuffing. Carve the duck and serve with the sauce.