Preheat the oven to 350 degrees F. Line a baking sheet with a silicone mat and coat lightly with cooking spray.
Drain and rinse the soaked quinoa; you should end up with approximately 1 1/2 cups.
Place the quinoa into a food processor along with the baking powder and salt; process until a smooth consistency, about 3 minutes.
Pour the batter into a piping bag and form x's and o's with the batter onto the prepared baking sheet. Bake for 20 minutes.
Take the crust out of the oven and pour some tomato sauce in each letter and sprinkle with some cheese. For the o's, top with pepperoni and for the x's top with the matchsticks of zucchini. Return the letters to the oven and bake until the cheese melts.