Sprinkle yeast over water in a small bowl; stir to dissolve yeast. Let stand about 5 minutes. Stir in flour and salt to make a soft dough. Turn dough onto a lightly floured surface and knead until smooth and elastic, about 5 minutes, adding more flour if necessary. Shape into a ball. Place in a greased bowl and turn to coat. Cover and let rise in a warm place until doubled in bulk, about 1 hour.
Preheat oven to 425°F. For pizza, sprinkle two large pizza pans or baking sheets with cornmeal. Punch down dough and divide in half; roll or pat each half into an 8-inch round and place on pizza pan. For focaccia, roll or pat all of dough into a 13x9-inch baking pan sprinkled with cornmeal. Top dough as desired and bake on lowest rack of oven for 20 minutes or until crust is golden brown.
Makes 6 servings.