In a large mixing bowl, combine the ground beef, finely chopped green onions, cilantro, grated ginger, minced garlic, oyster sauce, soy sauce, sugar, sesame oil, rice vinegar, and cornstarch. Mix everything together thoroughly using your hands or a wooden spoon until well blended.

Grease a heatproof dish with cooking spray or a light coat of oil. Layer the dumpling wrappers on the bottom of the dish, then spoon a layer of the beef filling over the wrappers. Continue alternating layers of dumpling wrappers and filling, finishing with a layer of wrappers on top.

Prepare your steamer by filling the bottom with water and bringing it to a gentle simmer over medium heat. Place the layered dumpling lasagna in the steamer basket and cover with a lid. Steam for approximately 20 minutes.

While the lasagna is steaming, whisk together the chili oil, soy sauce, sugar, rice vinegar, and sesame oil in a medium mixing bowl. Optionally, sprinkle in sesame seeds.

Once your dumpling lasagna is finished steaming, remove it from the steamer and let it sit for a minute. Drizzle the sauce over the top, and optionally garnish with sliced green onions. Serve hot.