Bring three cups of water to a boil (on the stove or in the microwave).
Combine all of the sauce ingredients in a medium bowl; whisk until well-combined. Set aside.
Drain the tofu and cut it into bite-sized cubes. Place the tofu in a colander and pour the boiling water over the top. Pat dry with paper towels, then transfer the tofu to a plastic zipper-close bag. Add the soy sauce, rice vinegar, and sesame oil to the bag. Seal the bag and give it a good shake. Re-open the bag and add one tablespoon of the cornstarch. Re-seal and shake to coat. Repeat with the remaining cornstarch, one tablespoon at a time, until the tofu is well-coated.
Heat the peanut oil in a large skillet or wok set over medium-high heat. Add the white parts of the scallions and stir-fry for 1 to 2 minutes, until browned. Remove from the pan and set aside.
Turn the heat down to medium. Add the tofu to the pan and fry until golden brown, about 1 minute per side (6 minutes total).
Give the prepared sauce a good stir and pour it into the pan. Toss with the tofu and allow to cook for 1 to 2 minutes, until thickened.
Turn off the heat and stir in the scallions (white and green) and orange segments. Garnish with sesame seeds and serve hot.
Notes
Store Orange Tofu leftovers in an airtight container in the refrigerator for up to 3 days. To freeze, just place it in a freezer-safe container for up to a month.To reheat, thaw if frozen, then warm in a skillet over medium heat until heated through, or microwave for 1-2 minutes.