Combine yeast, sugar and ½ cup very warm water in a bowl, let sit for five minutes. Combine flour and salt in the bowl. Mix yeast mixture with the bowl containing dry ingredients. Add a little extra flour if the dough is sticky. Knead for a good 10 minutes. Put into a greased bowl and let rise for 60 minutes until it doubles in size. Turn out onto a floured surface then knead lightly until smooth. Roll out into a ¼" thick, 12" diameter circle. The thinner the dough is rolled, the better.