Place the pancetta in a large pot placed over medium heat. Cook, stirring frequently, until the pancetta is golden brown and the fat has rendered out into the pan. Add the olive oil, then add the onion, carrots, celery, and garlic, kosher salt, and crushed red pepper flakes. Stir and drop the heat to medium low. Sweat the vegetables, stirring frequently, until they begin to soften, 7 to 10 minutes. Stir in the zucchini and cook for another 3 minutes. Add the cannellini beans, diced tomatoes, and tomato paste. Stir well, then add the kale, chicken broth or stock, rosemary, thyme, parsley, and parmesan rind. The kale may be mounding above the top rim of the stock pot. Don't worry. It will shrink to almost nothing! Raise the heat to medium high and bring to a boil. After it boils, drop the heat to medium low and let it simmer gently for 20 minutes.