Combine boiling water and 1/3 cup cornmeal in a bowl; let stand 20 minutes, stirring occasionally. Dissolve yeast in warm water in a small bowl, and let stand 5 minutes. Lightly spoon flour into dry measuring cups, and level with a knife. Combine cornmeal mixture, flour, and salt in a food processor, and pulse 4 times or until blended. With processor on, slowly add yeast mixture and oil through food chute; process until dough forms a ball. Process 1 additional minute. (To prepare dough by hand, combine cornmeal mixture, flour, and salt in a bowl; stir until well-blended. Add yeast mixture and oil, stirring well.) Turn dough out onto a floured surface, and knead lightly 4 or 5 times (dough will feel tacky).
Place dough in a bowl coated with cooking spray, turning to coat top. Cover; let rise in a warm place (85°), free from drafts, 1 hour or until doubled in size. (Press two fingers into dough. If indentation remains, the dough has risen enough.)
Punch dough down; cover and let rest 5 minutes. Divide dough into 4 equal portions, shaping each into a ball (cover remaining dough while working to prevent it from drying).
Roll each ball into a 10 x 6-inch oval. Place 2 ovals on a baking sheet lightly dusted with 1 1/2 teaspoons cornmeal. Repeat procedure with remaining 2 ovals on an additional baking sheet lightly dusted with 1 1/2 teaspoons cornmeal. Add toppings and bake according to recipe directions.
Note: If you use whole-grain cornmeal, which still contains some of the hull and germ of the dried corn kernel, you'll need to increase the flour to 2 1/4 cups.