Chop the cauliflower into medium-sized pieces and heat up your large skillet to high heat. Add the oil and place the cauliflower in the skillet and stir to cover with oil then place a lid on your skillet. You'll want the cauliflower to get a nice brown char on the outside but come back every now and then to turn it so it doesn't burn. Let the cauliflower cook, covered, for 20-25 minutes, or until tender.
Preheat oven to 450 degrees.
After cauliflower is done, let it cool down for about 5 minutes then put it in a large blender. Sprinkle the cornmeal on top, along with the eggs, Italian seasoning, cayenne pepper, and salt & pepper, to taste.
Puree the cauliflower until you have a thick but smooth batter.
Cover your pizza pan with parchment paper and pour the batter into the center of the paper. Spread out evenly until you have a 1/2 inch thick crust.
Bake for 20 minutes or until the crust is a deep, golden brown. I like mine darker, so I actually let it bake for a lot longer. It's really up to you.
While the crust is baking, prepare your chicken and toss it the BBQ sauce. Set aside.
When crust is done, top with the chicken, mozzarella, and red onions.
Place back in the oven to bake a little longer or until cheese melts.