To make the sauce, whisk the chili oil, sweet soy sauce, regular soy sauce, black vinegar, and garlic together in a bowl.
For the wontons, bring a large pot of water to a boil.
Add the ground pork, egg, Shaoxing wine, ginger juice, potato starch, toasted sesame oil, salt, Chinese five spice and white pepper to a bowl and use a gloved hand to first knead, and then beat the mixture together until uniform.
To wrap the wontons, place one wonton wrapper in the palm of your non-dominant hand and then add about 1 teaspoon of filling to the center of the wrapper.
Wet two edges of the wrapper with a finger dipped in a bowl of water.
Fold the wonton wrapper over the filling to form a triangle.
Place the index finger of your dominant hand below the center of the wonton, and then use your thumb and middle finger to press the corners of the wonton shut to seal it. This also forces out any air pockets, which will make your wonton explode when you boil it.
Bring the two long corners of the wrapper together at the center of the wonton and seal them together using a drop of water if needed.
Working in batches, boil the wontons until they float to the surface, and then continue to cook them for another 30 seconds. Your water should not stop boiling when you add the wontons. If it does, you either need to use a bigger pot with more water or add fewer wontons in the next batch.
Once the wontons are done, use a slotted spoon to transfer the wontons to a bowl. You don't need to drain all the boiling liquid as this helps the sauce spread around.
Drizzle the wontons with a generous amount of the spicy chili oil sauce and then garnish with scallions and cilantro.