Baked Sardines in Pepperonata

Name: Baked Sardines in Pepperonata
Ingredients: 4 red bell peppers; 1/2 cup olive oil, plus more for drizzling; 1/2 medium red onion, thinly sliced; 2 garlic cloves, thinly sliced; Kosher salt, freshly ground pepper; 2 tablespoons tomato paste; 1 tablespoon sugar; 1/2 cup dry white wine; 1/2 cup white wine vinegar; 2 tablespoons chopped fresh flat-leaf parsley; 2 tablespoons drained capers; 1/2 teaspoons dried oregano; 8 whole fresh sardines, scaled, gutted, deboned; Chopped fresh dill and grilled crusty bread (for serving)