1. Combine all ingredients except salt, pepper and lemons in a bowl.
2. Remove 2 cups of the mixture and reserve.
3. Using a blender or food processor, puree the remaining mixture in the bowl.
4. Add 2 cups of reserved mixture to the pureed mixture.
5. Season with salt, pepper (optional) and the juice from the lemons.
6. Cover mixture and refrigerate for at least 2 hours before serving.
7. Serve cold, garnished with chopped cilantro.