Heat a pan on low heat. Wash the duck breasts. With a knife make diagonal incisions on the surface of duck, all trough the fat, not the meat without cutting into the meat. Season with a little bit of salt and pepper, put in the pan, skin side down. Cook until skin is roasted, about 5 minutes. Turn over and cook the other side for a couple of minutes then turn again. Remove the grease but do not throw it away. Put the duck breasts in a dish and place in the oven for 7 minutes.
Heat the duck grease in a new pan, dice the onion and wash corn. fry in the pan for 5 minutes.
Take the duck out of the oven and set aside
Heat the taco shells in the oven
Cut the pears, endives, and coriander. Put in the pan with the corn and onion. Add the vinegar and season with salt and pepper.
Cut the duck into dices or slices and put in the pan for a couple of minutes.
Wash the spinach leaves and red cabbage
Take the taco shells out of the oven and prepare your tacos: first the spinach and red cabbage , then the duck, endives and pear salsa