Combine ground meat, Panko, ⅓ cup parsley, egg, 2 minced garlic cloves, 1 teaspoon salt and ½ teaspoon pepper. Mix just until combined.
Shape meat mixture into 1 ½-inch meatballs (#24 scoop / 1.5 ounces) and arrange on a plate.
Heat 2 tablespoons oil in a large pot or Dutch oven over medium until shimmering. Add half the meatballs in an even layer, and cook, without moving, until first side is dark brown, about 3 minutes. Using tongs, turn meatballs and cook until second side is well browned, about 3 minutes more. Transfer meatballs back to plate and repeat with remaining meatballs; set aside.
Heat remaining 2 tablespoons oil to now empty pot over medium until shimmering. Add onion and cook until softened, about 5 minutes. Add 2 chopped garlic cloves and 1 tablespoon salt (*see note) and cook 1 minute.
Add 8 cups water and bring to a boil over high heat, reduce to medium and simmer 8 minutes. Reduce heat to low and stir in meatballs, kale and beans; simmer until kale is just wilted.
Off heat, stir in remaining ⅓ cup parsley and season with salt and pepper to taste.