In a large bowl, combine the ground pork, shrimp, leeks, scallions, soy sauce, dark soy sauce, oyster sauce, chicken bouillon, sugar, black pepper, and garlic. Mix well until fully incorporated.
Place a wonton wrapper in the palm of your hand. Scoop about 1-2 tablespoons of the filling into the center of the wrapper.
Wet the edges of the wrapper with water, then fold the wrapper in half to form a half-moon shape. Press the edges to seal.
In a large skillet or wok, heat the neutral cooking oil over medium-high heat.
Working in batches, carefully add the dumplings to the hot oil and cook for 2-3 minutes per side, or until golden brown.
Serve the dumplings hot, with chili oil and black vinegar on the side for dipping.