In a small bowl soak mushrooms in 1/2 cup cold water for about 30 minutes to soften. When softened, drain and squeeze mushrooms dry, reserving the mushroom liquid. Cut off and discard stems and thinly slice caps. Rinse ham in cold water. In a small saucepan, bring 1 cup of cold water to a boil over high heat. Add ham and return to a boil. Reduce heat to medium-low, cover and simmer 20 minutes. Drain ham, and set aside until cool enough to handle. Slice the ham into paper-thin slices. Stack a few slices at a time, and cut into julienne strips to make about 1/2 cup. Cut chicken into scant 1/2-inch-thick slices, place in a medium bowl. Add mushrooms, ginger, rice wine, thin soy sauce, black soy sauce, cornstarch, sesame oil, sugar and pepper and mix with your hands to combine. Place the rice in a 2-quart saucepan. Wash the rice in several changes of water until the water runs clear. Drain the rice. Level the rice and add enough cold water to cover by 1-inch. (Or add 1 3/4 cups of water). Bring to a boil, covered, over high heat, never stirring the rice. Reduce heat to low and simmer, covered, 7 to 10 minutes or until the water almost completely evaporates. Meanwhile, stir 1 tablespoon vegetable oil into the chicken mixture and combine thoroughly. Heat a 14-inch flat-bottomed wok or skillet over high heat until hot but not smoking. Add the remaining 1 tablespoon vegetable oil to the wok and carefully add chicken mixture, spreading it in wok. Cook undisturbed 1 minute, letting chicken begin to brown. Then, using a metal spatula, stir-fry 1 minute or until chicken is lightly browned on all sides but not cooked through. Add mushroom liquid and ham and cook, stirring, 30 seconds. Uncover rice and quickly spread chicken mixture and scallions over it. Immediately re-cover rice and cook 5 to 10 minutes more or until chicken is just cooked through and rice is tender. Bring the pot to the table and serve immediately.