Place cabbage in a large mixing bowl. Add carrots, cucumber, mint and basil and gently toss.
Combine ginger, vinegar, fish sauce, sugar and salt. Whisk until sugar melts. Drizzle over cabbage mixture. Toss well, making sure everything gets coated with the vinaigrette. Cover and refrigerate 30 minutes. Just before serving, sprinkle with chopped peanuts if using.