Preheat oven to 375° F. Spray rack in roasting pan with nonstick cooking spray. Arrange duck breasts, skin-side up, on rack and roast until skin is crisp and browned, about 20 minutes.
While duck breasts are roasting prepare relish. In saucepan heat oil; add peppers and onions and cook over medium heat, stirring, until softened, 2-3 minutes.
In 1-cup liquid measure combine 1/2 cup water, the sugar, lemon juice, and cornstarch. Stir into pepper-onion mixture and cook, stirring, until mixture thickens.
Reduce heat to low; add cherries and let simmer until throughly heated, about 5 minutes.
To serve, remove and discard skin from duck. Serve duck breasts topped with relish.
Servings: 6 to 8