Place your chickpeas in fresh clean water with the whole garlic and bring to the boil, then simmer for approximately 2 hours, until cooked. Drain (keep the chickpea water, as it makes a very good vegetarian stock), put half the cooked chickpeas into a food processor with the tahini and peeled garlic, whizz, and add the lemon juice and some of the oil: you are looking for a looseish consistency, not a thick glump. Add the Tabasco, salt and pepper, and the rest of the chickpeas then whizz again, but keeping these coarser—coarse is good here.