In the bowl of a food processor, combine tahini and lemon juice. Process for 1 minute.
Add the olive oil, minced garlic, cumin and the salt to the food processor. Process for 30 seconds, scrape sides and bottom of bowl if some parts are not getting mixed. Process another 30 seconds.
Add half of the chickpeas to the food processor and process for 1 minute. Scrape sides and bottom of bowl, add remaining chickpeas and process for 1 to 2 minutes, or until thick and quite smooth.
To enhance smoothness, slowly add 2 to 3 tablespoons of water until the consistency is perfect.