In a large bowl, cover the lentils with boiling water by 2 inches and allow to sit for 15 minutes. Drain and set aside.
Meanwhile, heat the olive oil in a large (12-inch) pot or Dutch oven, such as Le Creuset, over medium heat. Add the onions and leeks and saute for 15 minutes, stirring occasionally, until the vegetables are translucent. Add the garlic, thyme, cumin, 1 tablespoon salt, and 1½ teaspoons pepper and cook for 1 minute. Add the celery and carrots and cook for 10 minutes, stirring occasionally. Add the chicken stock, tomato paste, and reserved lentils and bring to a boil. Reduce the heat and simmer uncovered for 1 hour, adding the kielbasa after 30 minutes. Add the red wine vinegar, taste for seasonings, and serve hot in large bowls, drizzled with olive oil and sprinkled with grated Parmesan cheese.
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