Using a fork, lightly beat eggwhites and a pinch of salt in a large bowl. Add chicken and stir to coat. Chill for 30 minutes.
Heat sliced ginger, sugar and 1/2 cup water in a small pan on high. Bring to a boil. Reduce heat to medium. Simmer for 10 minutes, until syrup is thick and ginger is tender. Remove from heat.
heat 4 cups water in a pan on high heat. Bring to a boil. Drain chicken. Add to boiling water. Cook, stirring once, for 1 minute, until white. Drain immediately. Pat dry with a paper towel.
Combine cornflower, rice wine, soy sauce, stock, sesame oil and 1 teaspoon water in a small bowl.
Heat peanut oil in a wok on medium. Stir-fry garlic and ginger matchsticks for 30 seconds, until fragrant. Add snow peas and stir-fry for 1 minute., until bright green. Add chicken and sir-fry for 30 seconds, until heated through. Remove from heat.
Pour onto a serving dish and scatter radish, chestnut and candied ginger over chicken mixture. Serve with the steamed rice.