Prepare the tofu: Drain and press tofu for 20 minutes to remove excess moisture. Cut into 1-inch cubes and pat dry with paper towels.
Coat the tofu: In a bowl, toss tofu cubes gently with cornstarch and salt until all sides are evenly coated.
Preheat the air fryer: Set the air fryer to 190°C (375°F) and preheat for 3 minutes. Lightly spray the basket with oil.
Air fry the tofu: Place the tofu cubes in a single layer in the fryer basket. Spray lightly with oil. Cook for 12 minutes, flipping halfway through until golden and crisp.
Prepare the sauce: In a small saucepan, mix dashi, soy sauce, mirin, and grated ginger. Heat on low for 2–3 minutes until fragrant.
Assemble: Place the hot tofu cubes in a shallow serving bowl. Pour the warm sauce over them.
Garnish and serve: Top with grated daikon, sliced green onions, sesame seeds, and chili flakes. Serve immediately for that perfect crispy-meets-soft texture.