Prepare the rice: In a small bowl, whisk together the rice vinegar, sugar, and salt until the sugar and salt are dissolved. Gently fold this mixture into the cold cooked rice, ensuring each grain is lightly coated. Be careful not to mash the rice.

Shape the rice: Line an 8x8 inch baking pan with plastic wrap, leaving some overhang. Press the seasoned rice firmly and evenly into the pan, aiming for a thickness of about 1/2 to 3/4 inch. The firmer you press, the better it will hold its shape. Cover with the plastic wrap overhang and chill in the refrigerator for at least 1 hour, or until very firm.

Cut the rice: Once chilled and firm, use the plastic wrap to lift the rice block out of the pan. Place it on a cutting board and cut it into desired shapes – squares (about 2x2 inches) or rectangles are common. If the rice is too sticky, slightly dampen a sharp knife.

Fry the rice: Heat about 1/4 inch of neutral oil in a large non-stick skillet over medium-high heat until shimmering. Carefully place the rice pieces into the hot oil, ensuring not to overcrowd the pan (work in batches if necessary). Fry for about 3-5 minutes per side, until deeply golden brown and crispy.

Drain and serve: Use a spatula to carefully remove the crispy rice from the pan and place them on a wire rack set over a baking sheet or on paper towels to drain excess oil. Serve immediately with your favorite toppings.