1. Heat olive oil in a saucepan and add the onions, chili peppers, and cook for about 10 minutes, add the spices and continue to cook until onions are tender.
2. Add the lentils, tomatoes, tomato puree, and add water just to cover.
3. Simmer for about 20 minutes.
4. Peel and cube the squash and add to the lentils. Simmer until tender.
5. Add the optional greens to pan during the last 5 minutes of cooking.
6. Serve with rice or couscous. (You could also prepare this stew with white beans.)