1) Combine all of the dough ingredients, mixing to form a cohesive dough.
2) Knead to make a smooth, fairly stiff dough. This will take about 6 minutes in a stand mixer equipped with a dough hook. You may also make the dough in your bread machine, set on the dough cycle.
3) Shape the dough into a ball, and let it rise in a covered bowl for about 90 minutes, till it's just about doubled in bulk.
4) Gently deflate the dough, and divide it in half.
5) Shape each half into an 18" rope.
6) Working with one piece of dough at a time, mark the center of the rope, and coil one end to the center.
7) Coil the other end, as pictured, to make an "S" shape.
8) Place the loaves on a parchment-lined or lightly greased baking sheet, and cover with lightly greased plastic wrap, or a large casserole pan, such as an oversized disposable lasagna pan.
9) Let the loaves rise for about an hour, till they're nice and puffy. Towards the end of the rising time, preheat the oven to 350°F.
10) Brush the loaves with the beaten egg white, and sprinkle liberally with the sesame or flax seeds.
11) Bake the loaves for about 25 minutes, till they're golden brown. Remove them from the oven, and cool on a rack.