Heat a large stockpot on medium heat for 3 minutes. Add chopped onion and fine sea salt. Saute for approximately 7 minutes, stirring occasionally. If you notice browning keep stirring, and if the browning does not get absorbed by the liquid, add in a tablespoon or two of water.
Add garlic, jalapeno, and red and green bell peppers. Stir for 3 to 5 minutes. Do not let garlic burn, add small increments of water if needed to prevent vegetables from sticking.
Add chili powder, cumin, and smoked paprika, and bay leaf. Stir for 30 to 60 seconds continuously to release flavors.
Stir in crushed tomatoes with juice, vegetable broth, pumpkin puree, kidney beans, pinto beans, black beans, tomato paste, and dried Arbol chiles if using (whole or chopped).
Cook on stovetop for several minutes on medium until bubbling. Reduce heat to medium-low, and let simmer for 20 to 30 minutes. Taste and adjust seasonings as necessary.
Remove bay leaf before serving and stir in lime juice. Serve in bowls and top with sliced green onion, chopped avocado, or cilantro.
Notes
Add one to three dried Arbol chiles, whole or chopped. Before the stew is ready to be served, you can take out the softened whole chiles, let them cool briefly, chop and add them back into the stew for extra flavor and spice.
If the soup is too thick, add more water or vegetable broth.