1. Process broth and all but 1 cup of beans in food processor until smooth, about 15 seconds, scraping sides of bowl with rubber spatula if necessary.
2. Add remaining beans and process until slightly chunky, about ten 1-second pulses.
3. Heat oil in 12-inch nonstick skillet over medium heat until shimmering.
4. Increase heat to medium-high; add onion, peppers, and salt.
5. Cook, stirring occasionally, until softened and beginning to brown, about 5 minutes.
6. Add garlic and cumin; cook, stirring frequently, about 30 seconds.
7. Add beans and stir until thoroughly combined.
8. Reduce heat to medium and cook, stirring occasionally, until beans are thick and creamy, about 5 minutes.
9. Stir in cilantro and lime juice, if using, and serve.