Place warm water in a small bowl. Sprinkle yeast and sugar over water, stirring until they dissolve. Let stand 5 minutes or until mixture is bubbly.
Combine flour and salt in a big bowl; make a well in center of mixture. Pour yeast mixture and oil into well, and stir to form a soft dough. Turn dough out onto a lightly floured surface, and knead 5 minutes. Spray inside of a big bowl with cooking spray, and place dough inside it. Lightly spray top of dough. Cover with plastic wrap, and refrigerate overnight.
Overnight the dough will rise and double in size. Punch dough down with your fist to release air. Divide dough into 8 equal portions, shaping each into a 3-inch ball. Loosely wrap each ball in plastic wrap, and chill in refrigerator.