(Option 1) Place eggplant in a large bowl and add water to cover. Add 1 teaspoon salt, mix well. Place a pot lid on top to keep the eggplant under water for 15 minutes. Drain and pat dry.
(Option 2) Spread the sliced eggplant out on a paper towel. Sprinkle Kosher salt on both sides of the eggplant slices. Allow to rest for 45-60 minutes. Pat dry without rinsing.
Combine the sauce ingredients in a small bowl, mix well.
Sprinkle eggplant with 1 tablespoon cornstarch and mix by hand, until eggplant is evenly coated with with a thin layer of cornstarch.
Add 2 tablespoons oil to a big nonstick skillet and heat over medium high heat until hot. Spread eggplant across the bottom of the skillet without overlapping. Cook the eggplant one side at a time until all the surfaces are charred and the eggplant turns soft, 8 to 10 minutes in total. Transfer the eggplants to a plate. If the skillet gets too hot and starts to smoke, turn to medium heat.
Add the remaining 1/2 teaspoon oil, the ginger and garlic into the same skillet. Stir a few times until fragrant. Add all the eggplant back into the skillet. Mix the sauce again until cornstarch is fully dissolved and pour it over the eggplant. Immediately stir a few times, until the eggplant is evenly coated and the sauce thickens. Transfer everything to a big plate.
Serve hot as a side or as main over steamed rice or noodles.