Combine the dressing ingredients in a small bowl, stir together, and set aside.
Combine the turnip, carrots, cucumber, celery, tofu, scallions, mushrooms, and cilantro in a mixing bowl and stir gently. Pour the dressing over them and stir gently again. Allow the mixture to stand for at least 30 minutes, stirring from time to time.
Just before serving, taste to see if you’d like to add more soy sauce, sugar, and/or vinegar. Sprinkle in some some red pepper flakes — enough to give the mixture gentle heat, but not to over power it.
Line a serving platter with shredded lettuce or kale, which help to absorb the plentiful marinade. Top with the optional cashew pieces or sesame seeds, and serve.