Smooth, unctuous tehinah, a sauce made from tehini (sesame-seed paste), is a felafel-topping mainstay; every felafel stand in Israel has a bowl or vat of it, along with at least one variety of hot sauce. Well-made tehinah should be fluid but not thin, and should nicely balance bitter, acidic, and garlicky flavors. Stir tehini before using, as the oil will have separated from the paste.