In a large skillet, heat the olive oil over medium heat. Season the chicken with salt and black pepper and add to the skillet. Cook until golden on both sides, about 10 minutes; transfer to a plate.
Pour out all but 2 tablespoons of fat from the skillet and add the bell pepper, onion and garlic; cook until softened, about 8 minutes. Stir in the tomato paste, then add the crushed tomatoes, bay leaves and crushed red pepper. Add the chicken and any juices; lower the heat, cover and simmer until the chicken is cooked through, about 25 minutes. Discard the bay leaves and stir in the cilantro; season with salt and black pepper.
Meanwhile, in a large pot of boiling, salted water, cook the spaghetti until al dente; drain. Top with the chicken and sauce.