Press the tofu: Drain the tofu and wrap it in a clean towel.
Place a skillet or a few books on top and let it sit for 15–20 minutes. This removes excess moisture and helps crisp it up.
Preheat the air fryer: Set it to 390°F (200°C) for 5 minutes. A hot basket helps prevent sticking.
Cube and coat: Cut tofu into 1-inch cubes.
In a bowl, toss with oil, salt, and pepper. Sprinkle on 2 tablespoons cornstarch and toss again until every side looks lightly coated and matte.
Arrange in the basket: Lightly spray the air fryer basket. Spread the tofu in a single layer with space between pieces.
Work in batches if needed to avoid crowding.
Air fry: Cook at 390°F (200°C) for 12–16 minutes, shaking the basket halfway. Tofu should be golden and crisp at the edges. Add 2–3 more minutes if you want extra crunch.
Make the sauce: While tofu cooks, whisk soy sauce, rice vinegar, hoisin, brown sugar, tomato paste, sesame oil, garlic, ginger, red pepper flakes, and water in a skillet or saucepan.
Thicken: Bring sauce to a simmer over medium heat.
Stir in the cornstarch slurry and cook 1–2 minutes until glossy and thick enough to coat a spoon.
Combine: Add the hot, crispy tofu to the pan and toss until every piece is lacquered in sauce. If the sauce seems too thick, splash in 1–2 tablespoons water to loosen.
Serve: Spoon over rice with a side of broccoli. Finish with green onions and sesame seeds for crunch.