Duck Confit Crostini with Pickled Cherries and Duck Cracklings

Bring vinegar, sugar, mustard seeds, rosemary sprig, chile, ½ tsp. salt, and ½ cup water to a boil in a medium saucepan. Reduce heat and simmer, stirring occasionally, until sugar and salt are dissolved, about 3 minutes. Mix in cherries, remove from heat, and let sit at least 1 hour to pickle mustard seeds.

Preheat oven to 425°. Arrange bread on a rimmed baking sheet. Drizzle with oil and season with salt and pepper. Bake until golden, 6–8 minutes.

Remove skin from duck; set aside. Pull meat from bones and finely chop; discard bones. Transfer duck to a medium bowl; set aside.

Cook reserved duck skin in a medium skillet over medium heat, pressing down with a spatula to help it make contact with the pan, and turning occasionally, until deep golden brown and crisp, about 6 minutes (resist the urge to turn up the heat; you’ll have better results if the fat slowly renders from the skin before crisping). Transfer skin to paper towels to drain; season with salt. Let cool, then crumble into small pieces. Pour rendered fat in skillet over reserved duck meat and toss to combine.

Strain ¼ cup cherries from pickling liquid and coarsely chop. Add cherries and 2 tsp. pickling liquid to duck mixture and toss to combine; taste and season with salt and pepper. Spoon duck mixture onto toasts, top with scallions, duck cracklings, and drizzle with pickling liquid.

Do ahead: Cherries can be pickled 2 weeks ahead; cover and chill. Duck mixture can be made and skin crisped 2 days ahead. Cover and chill duck mixture; store skin airtight at room temperature.