For the orange sauce: In a small bowl, mix the orange juice, sugar, soy sauce, cornstarch, ginger, garlic, sesame oil, and red pepper flakes. Set aside.
For the tofu: Use your fingers to tear it into chunks about 1" in size. Add the tofu to a medium bowl and sprinkle with 2 tablespoons of cornstarch. Toss to coat.
Heat the light oil over medium-high heat in a cast iron skillet or non-stick pan. Once hot, add the tofu, and cook for about 5 minutes, flipping as needed until the tofu is lightly browned all over.
Pour all of the sauce mixture into the pan with the tofu, and cook for another 2 - 5 minutes until the sauce thickens.
Serve the tofu with rice and garnish with green onions and orange zest if desired.
