In a large bowl, combine ground chicken, chopped spring onions, finely chopped shiitake mushrooms, minced garlic, minced ginger, light soy sauce, rice wine vinegar, sesame oil, sugar, ground black pepper, and MSG. Mix until well combined and silky.
In a 7"x9", 3" deep heatproof dish or tray, begin by spreading down a layer of the meat mixture (around a third). Lay down 9 dumpling wrappers with minimal overlap (like a lasagna). Top with another layer of the meat filling, then another layer of dumpling wrappers, then another layer of meat filling, then another layer of dumpling wrappers. Gently pour over 75ml water.
Place your heat proof dish in a steaming basket, and place on top of your pan which has around 2-3 inches of water in it. Add the lid onto your steaming basket and steam on high heat for 17 minutes.
Meanwhile, make your sauce by combining tahini, sugar, soy sauce, lime juice, sesame oil and minced garlic in a bowl. Stir to combine.
Once your timer has gone off and the wrappers are wrinkly and dimpled, delicately remove from the steamer. Drizzle over the tahini dressing, chilli oil, chives, and sesame seeds.
