Step 1Bring a pot of water to a rolling boil. Add the peaches and blanch 30 seconds. Cool slightly, then slide or pare the skins off. Cut the flesh into half-inch pieces and place in a clean, nonreactive saucepan.
Step 2Add the vinegar, lime juice, ginger, jalapenos, shallots, allspice, cloves, cinnamon stick and raisins, and mix well. Stir in the sugar. Bring to a boil, then reduce the heat and simmer, uncovered, 30 minutes or until thickened, stirring occasionally. Season with salt to taste and set aside.
Step 3Rinse the duck breasts and pat them dry. Using a sharp knife, carve off any excess fat and skin, then score the skin in a fine crosshatch pattern, without cutting into the flesh. Lay skin-side-down in the soy sauce in a shallow dish and marinate 30 minutes.
Step 4Heat a grill until very hot. Season the breasts with salt and pepper and lay skin-side-down on the grill. Cook 3 minutes, then turn slightly to leave a crosshatch grill mark on the skin. Cook 1 minute, then flip over and cook until done to taste, about 3 to 4 minutes longer for medium-rare. Transfer the breasts to a cutting board with a rim to rest for 5 minutes longer.
Step 5Serve the breasts whole or sliced, with warm chutney on the side (reserve the remainder for another use).