4 chicken leg quarters (about 10 oz. each)
1 1/4 teaspoons kosher salt
1 teaspoon black pepper
2 tablespoons grapeseed or avocado oil
1 yellow onion (about 10 oz.), chopped (about 2 cups)
2 bell peppers (about 7 oz. each), seeded and sliced
2 tablespoons drained capers
1 tablespoon minced garlic (from about 3 cloves)
1 tablespoon orange zest
1/2 cup dry red wine
1 28-oz. can diced tomatoes
3/4 cup kalamata olives, pitted and halved
1 tablespoon Italian seasoning
2 bay leaves
Chopped fresh flat-leaf parsley, for serving
Pat chicken pieces dry; sprinkle with 1 teaspoon of the salt and 3/4 teaspoon of the pepper. Heat oil in a large, deep skillet or Dutch oven over medium-high heat. Working in batches, place chicken pieces in a single layer, skin side down, in hot oil; cook until pieces are lightly browned and release easily from skillet, 5 to 10 minutes. Turn chicken and cook, turning pieces occasionally with tongs, until brown on all sides, 5 to 7 minutes more. Transfer to a plate.
Add onion, bell peppers, and capers to skillet and sprinkle with remaining 1/4 teaspoon each salt and pepper. Cook, stirring often, until vegetables have softened, about 5 minutes. Stir in garlic and orange zest; cook, stirring often, for 1 minute. Add wine and cook, stirring and scraping to remove any browned bits from bottom of skillet, until wine has almost evaporated, 1 to 2 minutes. Stir in tomatoes and bring to a boil. Stir in olives, Italian seasoning, and bay leaves.
Return chicken pieces to skillet. (They will not be fully submerged.) Reduce heat to low. Cover and simmer (do not boil) until a meat thermometer inserted into thighs registers 165 degrees, 30 to 40 minutes, uncovering during final 10 minutes to allow sauce to thicken. Discard bay leaves. Sprinkle with parsley and serve chicken with sauce.