Cut the stem off the eggplant and dice the eggplant into small cubes; sprinkle the cubes with salt and set in a colander to drain for about 15 minutes, then squeeze most of the liquid out.
In a small bowl, combine soy sauce, sugar, vinegar, and water.
Heat a wok over medium high heat and and add 1 tablespoon of dry sherry; stir fry the pepper flakes, ginger, and white part of the green onions until fragrant.
Add the eggplant, reduce heat, and saute about 8 to 10 minutes, stirring occasionally, until the eggplant is cooked through.
Add in the soy sauce mixture and turn the heat to high, cooking until most of the liquid is evaporated, about 5 minutes; be sure to stir so that the eggplant is thoroughly coated with the sauce.
Make a slurry with the remaining sherry and the cornstarch; add to wok and stir until thickened; toss in green onion tops.
Serve over plain white rice.