In a 6 to 8 quart slow cooker, combine the red onion, garlic, chili powder, cumin, paprika, sea salt, diced tomatoes, lentils, black beans, pumpkin puree, kale, and water or stock.
Cook for 6 hours on low heat, or until the lentils are tender.
Serve the chili with the lime wedges and any other toppings you desire (see suggestions above).
Stovetop instructions: in a large stockpot or Dutch oven, heat 1 tablespoon of olive oil. Sauté the onion over medium-high heat until soft, about 5 minutes. Add the garlic, chili powder, cumin, paprika and salt. Cook one minute more, until fragrant. Stir in the tomatoes, scrapping up any brown bits that may have formed on the bottom of the pan. Simmer, stirring occasionally, until slightly reduced, 5 minutes. Add the lentils, beans, pumpkin puree, kale, and stock or water. Bring to a boil, reduce the heat to medium low, and cook uncovered until the lentils are tender and the chili is thick, about 30 minutes.