In a heavy-duty blender or food processor, add beans, onion, garlic, tomato, and cilantro. Blend until smooth. Add avocados, lime juice, scallions, salt, pepper, and cumin. Blend until smooth and creamy. Transfer to a serving bowl and garnish with chopped scallions if desired.
Notes
This dip is delicious with crispy corn tortilla chips, bagel chips, pita chips, crackers, veggie sticks, or over crostini! It keeps well when kept in an airtight container in the fridge for several days.