Preheat the grill or broiler.
Cut the duck meat and pancetta into 1/4-inch cubes. Run the meat through a meat grinder.
Place the potatoes in a pan, cover with cool water and place over medium-high heat. Cook until just tender, then refresh in cool water and set aside.
In a large mixing bowl, combine the ground meat and the potatoes with the cinnamon, cumin, and salt. Mix very well, then divide the mixture into 8 equal oval patties, about 1/2-inch thick. Wrap each patty in caul fat. Place the patties under the broiler or on the grill and cook through, about 4 to 5 minutes per side. Set aside.
In a large 12 to 14-inch saute pan, heat the olive oil until just smoking. Add the garlic and saute until very light brown, about 2 minutes. Toss in the kale and saute, stirring quickly, about 2 to 3 minutes, until just wilted but not too soft. Remove from the heat and season with salt and pepper.
Divide the mixture evenly among 4 plates, place 2 crepinettes over each portion and serve with balsamic syrup drizzled over.