Cut tofu into 12 cubes. Place cornstarch on a plate or in a shallow bowl and dredge tofu in it, coating thoroughly.
Heat enough oil so that tofu will be half-way submerged. Fry tofu in hot oil for 3 to 5 minutes on each side, or until crispy. Drain on paper towels.
Sprinkle green onions over tofu and drizzle with hoisin sauce. Serve immediately.
