In a small bowl, combine the warm water, sugar, and yeast. Whisk and set aside to allow the yeast to activate, about 5 minutes, until foamy.
Meanwhile, in a separate medium bowl, add the white rice flour, quinoa flour, tapioca starch, potato starch, psyllium husk, and salt. Whisk to combine.
When the yeast mixture is foamy on top, add the olive oil and stir to combine. Pour the yeast mixture into the flour mixture and stir vigorously with a spoon just until smooth.
Place a 15x15-inch piece of parchment on a flat surface. Lightly oil the parchment paper with olive oil.
Scrape the dough with a spatula onto the center of the prepared parchment. Coat your hands with olive oil and press the dough into 14x10-inch rectangle with uniform thickness.
Place the pepperoni in a single layer over the dough. Leave a 2-inch border of naked dough along the 14-inch-long edge farthest away from you.
Sprinkle the shredded cheese on top of the pepperoni.
Starting at the 14-inch-long edge closest to you, roll the dough into a tight roll. Use the parchment paper as a tool to lift and roll the dough, only peeling away the parchment as you go, so that you're left with a tight roll whose outside is covered in parchment.
Open the parchment to expose the roll, and gently cut the roll into 12 slices.
Place the rolls on a fresh parchment-lined baking sheet. Allow to rise in a warm location for 60 minutes.
While the dough is rising, preheat the oven to 450º F. (If desired, add a small amount of additional shredded mozzarella cheese to top of each roll.)
Bake for 15 minutes until golden brown. Serve warm.
