Prepare the Wrappers
If using frozen wonton wrappers, thaw completely at room temperature until soft and pliable.
Prepare the Filling
Freeze the tofu overnight, then thaw completely. Press out as much excess water as possible.
Crumble the tofu and finely chop the garlic chives.
Heat a large pan over medium heat and add a little neutral oil.
Sauté the tofu and garlic chives for 3–4 minutes until excess moisture evaporates.
Season with vegetarian oyster sauce, Chinese five spice powder, and salt. Mix well.
Stir in the cornstarch to absorb moisture and help bind the filling.
Remove from heat and allow the filling to cool completely.
Fold the Wontons
Prepare a small bowl of water and carefully separate the wonton wrappers.
Place one wrapper on a clean surface or in your hand.
Lightly wet the edges with water using your finger.
Add 1/2 to 1 tablespoon of filling in the center.
Fold the wrapper into a triangle and press firmly to remove air pockets and seal the edges tightly.
Fold the triangle over and connect the bottom corners together using a dab of water to seal.
Repeat with remaining wrappers, covering finished wontons with a towel to prevent drying.
Cook the Wontons
Bring a large pot of salted water to a boil over medium-high heat.
Add 8–10 wontons at a time and cook for 2–3 minutes until they float and the wrappers become translucent.
Remove with a slotted spoon and transfer to serving bowls. Reserve the cooking water for the broth.
Make the Chili Broth
In a bowl, combine wonton broth, soy sauce, chili garlic sauce, doubanjiang, sugar, vinegar, sesame oil, and sesame seeds. Adjust seasoning to taste.
Pour the hot broth over the cooked wontons.
Garnish with chopped scallions and extra chili sauce if desired. Serve immediately.