Cook spaghetti according to package directions; keep warm. Combine turkey, 1/2 cup Parmesan, 1/4 cup chopped parsley, bread crumbs, egg, 1/2 teaspoon salt, and 1/4 teaspoon pepper in a bowl. Form into 15 meatballs; set aside. Heat olive oil in a large saucepan over medium-high heat. Add onion; cook until soft (5 minutes). Add garlic; cook 2 minutes. Stir in tomatoes, pinto beans, 1/4 teaspoon each salt and pepper; bring to a boil. Add meatballs; return to a boil. Reduce heat and simmer over low until meatballs are cooked through and sauce has thickened (15 minutes). Divide spaghetti, meatballs, and sauce among 5 bowls. Garnish with additional parsley and 1/4 cup Parmesan.