If using dried chili peppers, toast them in a dry skillet over medium heat or directly over a gas flame with tongs, turning as needed until fragrant. Set aside until cool enough to handle, then chop and remove seeds and stems. Blend with canned tomatoes until smooth.

In a medium Dutch oven or soup pot, warm 2 tablespoons of olive oil over medium heat. Add onion, bell pepper, and salt. Cook until the onion is tender and translucent, about 5 to 7 minutes.

Add garlic and cumin (and chili powder, if using) and cook until fragrant, about 30 seconds to 1 minute. Add the tomato-chili blend and cook for another minute.

Add beans and broth; stir to combine. Raise the heat to medium-high until it simmers, then reduce heat to maintain a gentle simmer. Simmer for 30 minutes.

Preheat the oven to 400°F. Line a large baking sheet with parchment paper. Toss tortilla strips with remaining 2 teaspoons olive oil and a sprinkle of salt. Bake until crisp and golden, about 8 to 12 minutes, tossing halfway.

Stir most of the cilantro into the soup, reserving some for garnish. Stir in 1 tablespoon of lime juice. Adjust salt and lime juice to taste.

Divide soup into bowls. Top with crispy tortilla strips, reserved cilantro, and additional garnishes as desired. Store leftovers for up to 5 days or freeze for future servings.