Mash the cooked rice or risotto to a very soft mush and keep it aside. Using a potato masher or a flat heavy spoon works well to mash. Also if using leftover rice, warm it up a bit to help mash it easily.
In a small pan, add 1 tbsp of oil and sauté the onion and bell peppers until soft. Also add the needed salt and crushed red peppers in it when cooking.
Cool it down a bit and then add this vegetable mixture to the mashed rice. Add the corn flour, all purpose flour and bread crumbs and mix well.
Take a handful of this mixture and make a ball with your palm. Stuff a piece of mozzarella inside the ball and close it well to form a tight ball. Do the same to the whole mixture and keep it aside.
Now form a breading station. In a wide bowl, combine the all purpose flour, corn flour, salt and pepper and add about ¼ cup of water. Mix it well to form a thick batter. In another wide plate, add the bread crumbs and season it (if needed).
Dip each of the formed rice ball into the batter and coat it evenly.
Now transfer this to the bread crumbs and roll it around to coat the surface. I would suggest using the left hand for the batter and the right hand for the bread crumbs, just to keep the wet and dry separately and not make it messy. Layer all the prepared ones in a tray and keep them ready to deep fry or Air fry. At this stage you could also freeze them to fry later.