Combine the rice and 2½ cups (600 ml) water in a medium pot. Bring to a boil, reduce the heat to low, and cover. Cook for 30 minutes, undisturbed. Turn off the heat and let stand for 10 minutes, then fluff with a fork.
While the rice cooks, cut the tofu into 1½-inch (4 cm) cubes and dredge in the cornstarch.