Heat 1 Tbs. of the oil in a 4- to 5-quart pot over medium heat. Add the onion, carrot, celery, and rosemary and cook, stirring occasionally, until the vegetables begin to soften, about 6 minutes. Add the tomato paste and garlic and cook until fragrant, 45 seconds. Add the broth, beans, kale, and Parmigiano rind (if using). Bring to a boil, reduce the heat to medium low, and simmer gently until the vegetables are tender, about 15 minutes. Meanwhile, heat the remaining 1/2 Tbs. oil in a 10-inch nonstick skillet over medium-low heat. Add the sausage meatballs, sprinkle with a pinch of salt, and cook, stirring occasionally, until browned and cooked through, about 10 minutes. Add the sausage to the soup and bring to a simmer over medium-high heat. Cook 5 minutes more to meld the flavors. Stir the cider vinegar into the soup and season to taste with salt and pepper.