- In large Dutch oven or saucepan set over medium-high heat, add oil. Add watermelon rind, garlic, celery, jalapeños, carrot, onion, red pepper, salt and black pepper; cook, stirring occasionally, for 5 to 8 minutes or until vegetables start to soften.
- Stir in chili powder, cumin, oregano, paprika, cayenne pepper and cinnamon. Cook, stirring occasionally, for 2 to 3 minutes or until fragrant.
- Stir in tomato paste and cook, stirring occasionally, for 1 minute. Stir in tomatoes (with juice), broth and vinegar; bring to a boil. Stir in lentils, kidney beans and bay leaves; bring back to a boil.
- Reduce heat to medium-low and simmer, stirring occasionally, for 45 to 60 minutes or until mixture has thickened and flavors are married.
- Remove from heat and stir in cilantro. Discard bay leaves.
- Serve chili with sour cream, cheese and crackers, if using.
- Substitute kidney beans with pinto or black beans if preferred.