Heat olive oil in a large pot over medium heat.
Add the diced onion and sauté until translucent, about 5 minutes.
Stir in minced garlic and jalapeño; cook for another minute.
Add the diced bell pepper and sauté for 3 more minutes.
Pour in the chicken or vegetable broth and bring to a boil.
Add the canned diced tomatoes and black beans.
Season with cumin, salt, and pepper; stir well.
Reduce heat and let simmer for 20 minutes to blend flavors.
Serve the soup hot, garnished with tortilla strips, avocado slices, and fresh cilantro.