Bring the vegetable stock, lentils, 1/2 teaspoon of salt and bay leaf to a boil in a saucepan over high heat. Reduce heat to medium-low, cover and cook until the lentils are tender, about 20 minutes. Add additional stock if needed to keep the lentils moist. Discard the bay leaf once done.
As the lentils simmer, heat the olive oil in a frypan over medium-high heat. Stir in the onion, thyme, oregano, salt and pepper. Cook and stir for 1 minute then add the sausage slices. Reduce the heat to medium-low and cook until the onion has softened, about 10 minutes.
Meanwhile, bring a large pot of lightly salted water to a boil over high heat. Add the kale and pasta. Cook until the pasta is al dente, about 8 minutes. Remove some of the cooking water and set aside. Drain the pasta then return to the pot and stir in the lentils and onion mixture. Use the reserved cooking liquid to adjust the moistness of the dish to your liking.