Dice the Dice the chicken to small-bite size cubes, about half-inch (1.5cm). Add the Kung Pao Chicken marinate for 10-15 mins. Gently stir-well. Set aside in the fridge.
Prepare the garlic, ginger, scallions, chilis, and peppercorns. Set the green scallion parts aside for garnishing. In a bowl, stir-well the Kung Pao sauce.
Preheat a large stainless steel skillet or wok over medium-high heat, when hot, add 1 to 1 ½ tbsp cooking oil. Add the chicken. Pan-fry them in a single layer so each piece gets crisp up in golden brown color, about 3 minutes. Then use a spatula with a firm tip to flip and cook for 1-2 minutes on the flip side. Transfer them to a plate to keep warm.
While the skillet is still hot, add 1 to 1 ½ tbsp more cooking oil. Add the aromatics. Season with a small pinch of salt and saute until fragrant, about 8-10 seconds. Take care not to burn the spices.
Add the chicken and pine nuts to the wok. Give the Kung Pao Sauce another stir before adding it to the wok. Quickly toss and stir-fry to coat the sauce over. Off heat. Serve hot and immediately. Garnish with green scallion parts. Drizzle with sesame oil, if using.
For a less-spicy or non-spicy version:
Substitute ¼ tsp ground black pepper + 2 tsp lemon zest for Sichuan Peppercorn.
Substitute tomato paste for Harissa chili paste.
Substitute red bell peppers for Chinese dried red chili peppers.
About the Sichuan peppercorns - Sichuan peppercorns can be used in two ways - 1) Used to fragrant the oil then scoop them out, if you aren’t used to the numbing sensation or 2) Leave them in the dish as most authentic Chinese dishes are kept in the dish. If you prefer to remove the peppercorns (i.e. only used to fragrant the oil), saute the peppercorns with oil first until the color turns dark brown, but not burnt. Remove them with a spatula then add the garlic, ginger, scallions...etc. About the Chinese Dried Red Chilis - Chinese dried red chilis - I use them in whole to add color to the dish. They do add a bit of spiciness to the stir-fry but not mouth-burning spicy as the seeds are contained inside. And most importantly, Do Not eat them. They are used for aroma and to fragrant the oil.