In a medium pot, heat the olive oil over medium heat. Add the diced onion and sauté for about 3-4 minutes until it becomes translucent.
Add the minced garlic to the pot and cook for another minute until fragrant.
Stir in the cumin, smoked paprika, and cayenne pepper, and cook for an additional 30 seconds, stirring continuously to release the spices' flavors.
Add the rinsed black beans and vegetable broth to the pot. Bring the mixture to a boil, then reduce the heat and let it simmer for 5-10 minutes.
Using a blender or immersion blender, blend the soup until smooth, or leave some chunks for a heartier texture based on your preference.
Stir in the lime juice and season with salt and pepper to taste. If the soup is too thick, add a little more vegetable broth to reach your desired consistency.
Serve hot, garnished with fresh cilantro and avocado slices for added creaminess.
Notes
Adjust the cayenne pepper to taste for desired spiciness.