Add olive oil to a large Dutch oven over medium heat. Add pancetta and cook for 4 minutes, stirring often. Add the onion, carrots and celery and cook until tender, stirring often, about 8-10 minutes. Add the garlic and cook an additional minute. Stir in the lentils, crushed tomatoes, chicken broth, paprika, thyme leaves, cumin, salt, pepper and bay leaf. Bring to a boil, then reduce the heat and simmer, covered, until the lentils are tender, about 35 minutes. Add the chick peas and balsamic vinegar and cook for an additional 5 minutes, until heated through. Remove bay leaf. Season to taste and serve with chopped fresh cilantro, if desired.