In the base of a 7 cup food processor fitted with a steel blade, combine the tahini, olive oil, lemon juice, garlic, salt, cumin, coriander and ¼ cup of chickpea liquid. Process for one minute.
Add the chickpeas, then blend for 1 minute on low, gradually adding in 1-2 tablespoons of extra liquid reserved from the can of chickpeas through the chute in the food processor lid.
Scrape down sides of processor, then blend for 1-2 minutes on high, adding in more liquid if you'd like it thinner. Blend until smooth and creamy.
Serve with veggies or crackers.
