Add the cooking oil into the wok. Let it heat up for about 8-10 minutes over medium heat.
Spread 4 tbsp/ 40g of crispy flour evenly over a plate. Set it aside.
In a mixing bowl, add 80g of crispy flour, garlic powder, pepper, and 75ml of water. Mix thoroughly with a whisk. Add 25ml of water if the batter is too thick. The consistency should be runny enough that it falls off the whisk easily. Set aside.
Cut the chicken breast into half, and then into thin strips of 3.5-4 inches in length and about 0.5 inches thick. Repeat for the other half of the chicken breast.
Marinate the chicken strips evenly with salt.
Crack an egg over the chicken strips, and mix until they are well-combined. This is optional.
Pour all the marinated chicken strips into the flour batter. Mix until they are well-combined.
Submerge the tips of wooden cooking chopsticks into the oil. When bubbles form at the tip, it is ready for deep frying.
Take a chicken strip, shaking off any excess flour batter. Gently slide it across the plate with dry crispy flour, coating all the chicken's surface as much as possible. Add it gently into the hot oil. Repeat with the rest of the chicken strips, until the wok is completely full.
Fry the chicken fingers in the hot oil for about 8 to 10 minutes over medium heat, or until they are evenly golden brown. Turn and rotate the chicken fingers occasionally for even cooking.
Once they are crispy, remove them from the hot oil with a wide strainer, shaking off the excess oil. Set them aside in a cooling rack. With a smaller and finer mesh strainer, scoop up flour and/ or chicken bits left in the oil.
Take the chicken strip, coating it in a thin layer of dry crispy flour, before submerging it in the hot oil. Repeat until the wok is full, or until there are no more chicken strips left. Deep fry the chicken for another 8 to 10 minutes, or until they turn golden brown.
Remove the chicken fingers from the hot oil with the wide strainer, shaking off excess oil. Set them aside in the cooling rack. Transfer the chicken fingers to a serving plate, and serve with some Thai Chicken Chilli Sauce as a dipping sauce.