Line 2 baking sheets with parchment or lightly grease.
Place the sugar in a small bowl. Stir in the cinnamon, if using.
Very lightly grease a large work surface with olive oil or lightly flour.
Divide the dough into 2 equal pieces. Cover one half with a towel.
Roll the other half on the work surface into a large, thin circle.
Cover the circle with a thin layer of tahini, leaving about 1/2-1 inch (1.25-2.5 centimeters) around the edge clear.
Sprinkle with up to 1/2 of the cinnamon sugar, to desired sweetness.
Make a cut in the center of the dough and tear lightly to create a hole. Gently, but tightly, roll and stretch the dough from the center hole towards the outside edges. (Optionally, you could simply roll the dough into a large, thin rectangle, spread with the tahini, add sugar, and roll long side to long side. If doing this, I like to slightly roll in the short sides once to form a barrier to keep the filling from seeping out).
Cut through the circle to make a rope. Pinch the ends to seal and prevent the tahini from leaking out.
Gently roll and stretch the dough to make the rope even and no more than 1 inch (2.5 centimeters) wide, then cut the rope into 4-6 equal pieces.
Pinch each of the ends to seal in the filling.
Place one of the pieces on the work surface, covering the others with a towel.
Gently roll the piece into a long, thin rope. Coil the rope, end to end, into a snail shape, tucking the outer end under the pastry to keep it from unraveling.
Using a rolling pin, roll the coil into a thin circle about 4-6 inches (10-15 centimeters) wide, as thin as possible and up to 1/3 inch (8 millimeters) thick (depending on desired thickness of the bread).
Place the bread on the prepared baking sheet and cover with a towel.
Repeat with the remaining pieces, then the remaining dough half, placing the shaped bread at least 1 inch (2.5 centimeters) apart on the baking sheets. Allow to rest at room temperature until lightly puffed, about 20 minutes.