On a lightly floured work surface, stretch each piece of dough out to a 14-inch round. Lift 1 dough round onto a floured board or pizza peel. Brush with 2 teaspoons of the olive oil and season with salt. Slide the dough onto the hot stone and bake for 5 minutes, or until lightly browned. Slide the crust back onto the peel and spread with half of the hummus. Return the pizza to the oven and bake for 2 minutes longer, or until deeply golden. Repeat to make a second pizza, using the remaining dough, another 2 teaspoons of olive oil and the remaining hummus.