Drain and wrap the tofu block in some paper towel, gently press to release excess water, cut into about 3/4 inch cubes;
Toss the tofu cubes in a flat plate with the arrowroot powder or cornstarch, evenly coat each cube;
Heat a large drizzle of oil in a nonstick frying pan over medium-high, pan-fry the tofu till all sides are golden crispy, about 3 - 4 minutes per side, remove from the pan and set aside;
Zest 1 orange, only the colored part not the white part, add zest to a mixing cup;
Squeeze the 1 and 1/2 orange for juice into the same cup;
Add all the rest of the sauce ingredients and whisk till smooth and well combined;
In the same frying pan, heat another small drizzle of oil, sauté the garlic and scallions till aromatic;
Slowly pour in the sauce, turn down the heat to medium, stir and bring the mixture to a gentle boil;
Transfer all the fried tofu into the pan, stir and toss to coat, continue to stir as the sauce thickens, remove from the heat when you reach preferred sauce consistency;
Serve with steamed white rice, choice of veggies, and sprinkle of sesame seeds and more scallions. Enjoy!