Preheat the oven to 400ºF.
Once the frozen riced cauliflower has been thawed, transfer it to a clean, thin dishtowel. Wrap up the steamed rice in the dishtowel, twist it up, then SQUEEZE all the excess moisture out! (Be careful if your cauliflower is still hot; let it cool before handling.) A lot of extra liquid will be released, which will help you avoid a soggy pizza crust.
In a large bowl, mix up the squeezed-out rice, egg, cheese, oregano, and salt. It won’t be like any pizza dough you’ve ever worked with, but don’t worry, it will work!
Press the dough out onto a baking sheet lined with parchment paper. (It’s important that it’s lined with parchment paper, not wax paper, or it will stick.) Keep the dough about 1/4-inch thick. Wet your hands to prevent sticking, if needed.
Bake for 30 minutes at 400ºF or until the top looks dry and golden.
Add your favorite pizza toppings to the crust, such as sauce and cheese, then return the pizza to the 400ºF oven. Bake an additional 5-10 minutes, just until the cheese is hot and bubbly. Slice and serve warm.