In a medium saucepan over medium-high heat add the duck skin and water and cook until the water has evaporated, the fat has rendered out of the skin (the yield will range from about 1/2 cup to 1 cup depending on the size of the duck), and the skin is brown and crispy. Strain.
Preheat the oven to 400 degrees F.
Heat a large skillet over medium-high heat. Add the duck fat, potatoes, garlic, pinch salt, thyme, and rosemary. Toss together to coat well. Cook 5 minutes on the stovetop and then place the skillet in the oven for 5 minutes, or until the potatoes are nicely browned and tender.
NotesServe with a garlic aioli, and garnish with chopped cracklins and sea salt.