Pour enough oil in a heavy large saucepan to reach the depth of 3 inches. Heat the oil over medium heat to 350 degrees F.
Stir the eggs, risotto, Parmesan, and 1/2 cup of the bread crumbs in a large bowl to combine. Place the remaining breadcrumbs in a medium bowl. Using about 2 tablespoons of the risotto mixture for each, form the risotto mixture into 1 3/4-inch-diameter balls. Insert 1 cube of mozzarella into the center of each ball. Roll the balls in the bread crumbs to coat.
Working in batches, add the rice balls to the hot ail and cook until brown and heated through, turning them as necessary, about 4 minutes. Using a slotted spoon, transfer the rice balls to paper towels to drain. Season with salt. Let rest 2 minutes. Serve hot.