Preheat oven to 400°F. In a large bowl, mix together flour, sugar and salt. Add 1 egg white, butter and 2/3 cup water to flour mixture. On a lightly floured surface, knead dough until smooth, then divide into 8 to 10 pieces. Roll each piece into a very thin circle. In a small bowl, mix remaining egg whites and water. Lightly brush each circle with egg white mixture then sprinkle about ½ tsp. sesame seeds on top. Bake on un-greased baking sheets for 10-15 minutes or until hard and golden brown.
