Place two 1-pound balls of pizza dough in two separate oiled bowls, and cover with damp tea towels. Allow the dough to rise for 1 1/2-2 hrs, until double in size.
For the chicken, drizzle the chicken breasts with olive oil. Mix the spices and salt in a small bowl and sprinkle liberally all over the chicken, then rub in the spices. Cover and refrigerate for at least 30 minutes. Then grill the chicken over medium heat for 8-12 minutes. Once cool, chop into bite size pieces.
Once the dough has risen, preheat the grill to high heat and place a grilling stone or pizze stone on the grates. (You could also place a baking stone in the oven at 500 degrees F.)
Punch down each dough ball and roll (or stretch) the dough out into a thin 14-inch circle. Brush the surface with oil and allow the dough to rise a few more minutes while you chop the toppings.
Sprinkle a tablespoon of cornmeal over the surface of two flat cookie sheets. Transfer the pizza doughs onto the cookie sheets and re-stretch if needed. Spread 1/4 cup enchilada sauce on each crust, then sprinkle with half the chopped chicken, 1/2 cup enchilado cheese, and 1/2 cup queso fresco.
With a gentle thrust, slide one pizza off the cookie sheet onto the hot grilling stone. Close the grill cover and grill for 7-10 minutes until the crust in bubbly and brown on the bottom. Use the cookie sheet to remove it from the grill, and repeat with the remaining pizza.
Once the pizzas are grilled, top each with fresh tomatoes, avocado, scallions, and cilantro. Pour the crema Mexicana in a squirt bottle and drizzle over the top of each pizza. Cut and serve.