Soak chiles in vinegar for 15 minutes. Add garlic and ginger and blend into a puree. Scrape mixture into a small bowl.
Add cumin, coriander and cinnamon and mix thoroughly. Coat duck pieces well with spice paste. Cover and refrigerate for at least 2 hours. Heat oil in a large Dutch oven over medium-high heat.
Add duck pieces and brown on all sides. Add salt, water, sugar and any remaining spice puree. Bring to a boil. Cover and simmer, stirring occasionally, until duck is tender, about 1 hour.
Skim off all fat. Transfer duck to a heated platter, pour sauce over, and garnish with minced cilantro.
Servings: 4 to 6