The secret to hummus is to boil dried garbanzo beans with a spoon full of baking soda....This trick was given to me by my BIL who owns a restaurants in Jordan which serve hummus....After that you want to grind it in the food processor. I always add a very descent amount of tahini, and lemon juice, and some water left over from boiling the hummus, and garlic smashed up very very well. Traditional hummus, doesnt have cumin or allspice, or anything of that sort. I have seen recipes that include it here on zaar, but in true reality hummus is a very simple dish. Usuualy dont need to add too much salt when using baking soda, for the baking soda adds a salty taste and seems to help the garbanzo beans to cook faster.
I would never buy tahini from a local grocers unless that grocers is a middle eastern grocer....only because there is a difference between what is authentic and not.
Here is a major distributor that carries most if not all the products we use in middle eastern cooking.
http://ziyad.com/