Heat the avocado oil in a large pot over medium heat. Add the diced onion and bell pepper and sauté for 3-4 minutes, until softened. Add the garlic and cook for another minute until fragrant.
Add spices:
Stir in the cumin, smoked paprika, and chili powder, cooking for 30 seconds to release their flavors.
Simmer the stew:
Add the black beans, vegetable broth, diced tomatoes, and salt to the pot. Bring the mixture to a boil, then reduce the heat to low and simmer for 15 minutes to allow the flavors to meld. Remove half of the stew and blend in a blender until smooth. Return to the pot and stir to combine.
Finish with lime:
Remove from heat and stir in the lime juice. Taste and adjust seasonings if needed.
Serve:
Ladle the stew into bowls and garnish with salsa macha and fresh cilantro, if desired.