Preheat the oven to 200C/400F/Gas 6.
For the duck, place the duck skin-side down in a non-stick ovenproof pan. Gradually bring up to a medium heat and fry the duck, draining off the excess fat into a bowl as it's released. Once the fat has rendered and is crisp, turn the duck over and cook on the other side for 2-3 minutes, or until golden-brown.
Transfer the pan to the oven and cook for 8-10 minutes, or until the duck is cooked to your liking.
Meanwhile, for the plum sauce, heat the butter in a pan. Add the sugar, chilli and red wine and bring to the boil. Stir frequently to dissolve the sugar.
Once the wine has reduced by half, add the plum pieces and cook for 2-3 minutes until slightly softened.
Add the cornflour mixture and stir until the sauce thickens. Season, to taste, with salt and freshly ground black pepper.
For the potatoes, place the cooked new potatoes into a bowl and season with salt and freshly ground black pepper. Add the olive oil and crush the potatoes with a wooden spoon.
Add the peanuts and dill and stir well.
To serve, place the duck onto a serving plate with the potatoes and drizzle over the plum sauce.