Preheat your air fryer (if it has a preheat function).
Add the flour and water to a mixing bowl and stir to form a runny paste. Scatter the panko breadcrumbs and salt on a large plate.
Cut the tofu into 2.5-3 cm cubes, dip them into the flour paste, then coat with panko bread crumbs.
Arrange the tofu in a single layer in the air fryer basket. Spray olive oil over the top. Air fry for 12 minutes at 190℃ (350℉), shaking the basket halfway through (at 6 mins). You may need to do this in batches, depending on the size of your air fryer.
Serve the tofu warm with a dipping sauce or as a main meal. It's excellent in a salad bowl or as a chicken substitute in katsu curry.
Notes
Storage
Crispy tofu tastes better fresh whilst it's still warm. Leftovers can be stored in the fridge in an airtight container for up to 3 days.