Begin by heating the olive oil in a large pot over medium heat. Once hot, add the diced yellow onion and sauté until translucent, about 5 minutes.
Next, stir in the minced garlic and diced red bell pepper, cooking for an additional 2-3 minutes until fragrant.
Sprinkle in the ground cumin, smoked paprika, ground black pepper, kosher salt, and ground oregano. Stir well to coat the vegetables in the spices and allow them to toast for about a minute.
Pour in the cooked black beans and the can of diced tomatoes (with their juices). Mix everything together, allowing the flavors to meld for a couple of minutes.
Pour in the vegetable broth and bring the mixture to a gentle boil. Once boiling, reduce the heat and let it simmer for about 15 minutes, stirring occasionally.
After simmering, taste the soup and adjust the seasoning, if necessary. To serve, ladle the soup into bowls and top with diced avocado, fresh cilantro, and a squeeze of lime juice.