Cook beans according to package directions. Season to taste with salt. Reserve in the cooking liquid (can be made a day ahead). In a high-sided pot, heat 1 teaspoon of the oil over medium heat. Add the diced sausage and cook until the meat is lightly browned, about 4 minutes. Remove the sausage from the pan. Pour the remaining oil into the same pan, and add the carrots and onion. Cook, stirring often, until softened, about 12 minutes. Add the kale and cook until wilted. Add the sausage and beans to the pot, and enough cooking liquid (or water, if necessary) to just cover the ingredients.
Heat until warmed through, and serve.