Press your tofu to remove some liquid. Cut the tofu in 3 "slabs" from the top to the bottom so you'll have 3 flat pieces.
You are going to have 3 dishes for dipping and coating. Place the flour in one dish. Mix the cornstarch and water in a separate shallow dish. Mix the panko bread crumbs with the salt and pepper in another shallow dish.
To bread the tofu, take one piece and coat each side in flour. Next, dip it in the cornstarch and water mixture insuring it's fully coated. Lastly, press it into the panko bread crumbs, both sides, making sure it's completely covered.
Repeat with the other two pieces of tofu.
Spray the basket of the air fryer with oil spray. Place the tofu inside and also spray the top of the tofu. The oil spray helps the panko brown. Bake at 390° for 7 minutes, flip and bake for an additional 7 minutes.
Slice the tofu in thin strips. Serve over rice with tonkatsu sauce on the side, if desired. (Sauce recipe in comments.)
Notes
I highly recommend freezing and thawing the tofu before pressing and using it. It’s a simple step that gives the tofu a meatier texture.
For each breading step, make sure the tofu is completely covered, including the sides.
Make sure you liberally spray the tofu and air fryer basked with oil spray to help it get crispy and browned.
Tonkatsu sauce: Mix together ½ cup ketchup, 2 tablespoons soy sauce, ¼ cup vegan Worcestershire sauce, 1 teaspoon Dijon mustard, and 2 teaspoons sugar.