Using a sharp paring knife, carve a Jack O'Lantern face into the side of each pepper. Season the inside of each bell pepper with salt and pepper. Set aside for filling. Preheat oven to 400°F. Heat oil in a large skillet over medium-high heat. Add onion and cook, stirring occasionally, until tender, about 3-5 minutes. Add ground chicken and sauté, breaking up into small crumbles with a wooden spoon as it cooks. Cook for about 8 minutes, until chicken is cooked through and begins to brown. Stir in tomato paste, garlic, chili powder, coriander and paprika, and cook until fragrant, about 1 minute. Remove from heat. Stir in black beans, tomatoes, corn and rice until combined. Place peppers, cut-side-up, in a 9x13-inch baking dish. Spoon chicken mixture into each pepper and top with cheese. Cover baking dish with aluminum foil. Bake until peppers are tender, about 25-30 minutes. Uncover and continue to bake until cheese is bubbling and light golden-brown, about 10 minutes. Top with parsley and serve.