To make the ranchero sauce, heat olive oil in a saucepan over medium heat. Add the bell pepper and onion and cook until soft, stirring occasionally to avoid burning, about 7–9 minutes.
Season the bell pepper and onion with salt and pepper and add the chipotle pepper and water to the pan. Continue to cook over medium heat, bringing the water to a boil, then lower the temperature and simmer about 5 minutes, until the water has reduced by half, leaving approximately 1⁄4 cup in the pan.
Remove mixture from heat and transfer to a blender. Blend over high speed until creamy.
To make the chipotle mayo, combine all ingredients in a blender and blend until smooth.
To make the pizza, first remove corn husk and all stray corn silk. Set a gas burner on medium-high heat. Using a pair of long kitchen tongs, sear corn over the flame, being careful to rotate so as not to burn the kernels. You want the surface to be lightly charred; this will take 1–2 minutes. Remove from heat and let cool before cutting the kernels from the cob with a knife. Set aside.
An hour before cooking, place pizza stone in oven and preheat to 500°F.
While the oven preheats, prepare the dough. Dust a clean countertop with flour to prevent the dough from sticking.
To stretch the dough, start by pressing down in the center of the ball, using your fingers to flatten the center. Gently push the dough out from the center to form the crust, leaving a 1 1⁄2-inch rim around the of the pizza. Stop when the pizza is approximately 12 inches in diameter. Transfer it from the countertop to a pizza peel.
Spoon the ranchero sauce over the dough, leaving 1 1⁄2 inches from the edge. Scatter the Oaxacan cheese and the roasted corn evenly over the pizza.
Transfer the pizza from the peel to the pizza stone. Bake at 500°F for 7–9 minutes. Remove the pizza from the oven.
Add teaspoon-size dollops of chipotle mayo across the pizza. Sprinkle evenly with cotija cheese. Squeeze the lime juice over the pizza. Garnish with cilantro.