Optional but recommended: press the 14 ounces extra-firm tofu to remove excess moisture. Wrap the block in a clean kitchen towel or paper towels, set it on a plate, place a heavy skillet or another weighted object on top, and let sit for 30 minutes.
Preheat the air fryer to 400°F.
In a large bowl, combine ½ tablespoon avocado oil, 2 tablespoons tamari, and ½ teaspoon sriracha.
Cut the pressed tofu into cubes and add the cubes to the bowl with the sauce. Gently toss the tofu to coat all pieces evenly.
Sprinkle 1 tablespoon cornstarch over the coated tofu and toss again until the tofu is evenly dusted.
Arrange the tofu cubes in a single layer in the air fryer basket with space between pieces; do not overcrowd. Work in batches if necessary.
Air fry for 11 to 15 minutes, flipping the tofu halfway through cooking, until the edges are golden brown and crisp. Timing may vary by air fryer.
Repeat with any remaining tofu and use immediately as desired.