Place the tofu in a tofu press, or on a plate between paper towels with something heavy on top, and press for at least 15 minutes to remove the excess water. The less water in the tofu the better the texture.
Slice the tofu into cubes. See the photos in the content above.
In a large bowl, toss the cubed tofu with the 1 cup of tapioca starch until all sides are coated in the starch.
In a wok or a cast-iron skillet, heat the ¼ cup of vegetable oil on high heat. When the oil is hot (add a bit of extra starch from the bowl to the pan, if it sizzles, it’s ready), add the tofu evenly in the pan. Use a metal spatula to turn the tofu often. You want all sided to get crispy and brown. Add a tablespoon of extra oil if needed.
After about 10 minutes, the tofu should have a lightly browned and crispy crust. Now add half of the chili garlic sauce and use the spatula to gently toss the tofu to coat all sides in the sauce. If you’re not stir-frying vegetables, use all of the sauce for the tofu, otherwise, use half of the sauce for the vegetables.
If you’re going to stir fry vegetables, remove the tofu from the pan and add another tablespoon of oil and cook the veggies. When they’re done, coat them in the other half of the sauce and add the tofu back to the pan to heat it.