Heat a 14-inch flat-bottomed carbon-steel wok (or a 12-inch stainless-steel skillet) over high heat until a drop of water vaporizes within 1 to 2 seconds of contact. Swirl in 1 Tbsp. vegetable oil. Add ginger; stir-fry until fragrant, about 10 seconds. Push the ginger slices to the sides and add the chicken in an even layer. Cook, undisturbed, until it begins to brown, about 1 minute. Using a metal spatula, stir-fry the chicken until lightly browned but not cooked through, about 1 minute more. Transfer to a plate.