To rice the cauliflower, cut florets into chunks and pulse in a food processor until you see rice-like bits. Do not over process -- you don't want mush. Microwave the riced cauliflower in a bowl for 5-8 minutes depending on your microwave. No need to add water. After microwaving, transfer riced cauliflower to a fine mesh strainer and drain completely, gently pressing out excess water. Transfer riced cauliflower to a clean dish towel and wrap the sides around the cauliflower while gently pressing out excess water. This drying process is important! Cook chicken. Preheat oven to 450 degrees. Spray a cookie sheet with non-stick, non-fat cooking spray. In a bowl, combine 2 cups riced, cooked cauliflower, 2 egg whites and any seasonings. Making sure everything is well mixed, place your "dough" on the cookie sheet and pat out to 9" round. Be sure not to press it too thin as it's easy to create holes. Bake at 450 degrees for 15 minutes. Remove from oven. Add BBQ sauce and toppings to your cauliflower pizza. Place pizza under broiler for 1 to 2 minutes once you've added all of your healthy toppings.