Be sure to use only rapid-rise yeast to make this easy pizza dough; regular dry yeast has to be activated with hot water before it's added to the flour mixture.
Make the dough: In a food processor, pulse together flour, cornmeal, yeast, and salt. With processor running, add oil and then 2 cups cold water in a steady stream; process until dough just forms a ball.
Turn out dough onto a floured work surface. Knead until smooth and elastic, 3 to 4 times. Place in a resealable plastic bag; let rise until doubled in bulk, 2 hours at room temperature or overnight in the refrigerator (let come to room temperature before proceeding, about 40 minutes).
Divide dough into four equal portions; roll into balls, and cover with a clean kitchen towel or plastic wrap until puffed, about 20 minutes.
Preheat oven to 500 degrees. Place each dough ball on a baking sheet; using your hands, gently flatten, and pull into 8-by-10-inch ovals. Top as desired.
Bake until crust is golden brown and toppings are hot, rotating sheets halfway through, 10 to 12 minutes.