Well, here's a recipe I came up with. Your request was kind of like a game my wife and do - name three ingredients and the other person has to come up with something. My wife added plantains to the mix (I don't know why!). In the process the chiles kind of took on a secondary role. Anyway, the cilantro sauce is inspired by a cilantro/cumin/habenero sauce from a restaurant, but here it's milder and sweet to go with the duck. This should serve about 4 people.

Cut the duck into bite-sized slices and mix with the marinade. Let stand for 3 or 4 hours (at least). Meanwhile, toast the cumin seeds until fragrant and grind into a powder. Puree the cilantro, pumpkin seeds, cumin and chiles (seeds and all). Add salt to taste. Roast and peel the chiles. Deseed and cut into strips. Set aside. Boil the plantains, let them cool, peel, and slice into rounds about 1/4" thick. Put them in a pot with the hominy, stock, and salt to taste. Bring to a boil then simmer until tender. Drain and keep warm. Remove the duck from the marinade (reserve the juice) and dry. Melt the butter in a heavy skillet at medium/high heat. Sear the duck in the pan, add the chiles, bring back to heat, then remove, and set aside (leaving the juices in the pan). Add the sugar to the pan and cook until it any remaining liquid boils away and the sugar starts to carmelize. Add the marinade, bring to a boil and then reduce to about 1/2 c. Pour the hot marinade into the cilantro/cumin mix and process until smooth. It should be a thick saunce, almost a paste. On a platter make a bed of hominy and plantains with the duck and chiles mounded in the center. Garnish with fresh cilantro and dollops of the sauce, serving the rest on the side.