Whisk together the rice vinegar, sesame oil, 3 spring onions, garlic, sugar, ginger, soy sauce, vegetable oil, coriander and mustard in a mixing bowl until the sugar has dissolved. Pour half of the dressing into another container, and refrigerate for later. Place the chicken breasts into the remaining dressing, and coat on all sides. Cover, and refrigerate 30 minutes to 1 hour.
Preheat an oven to 180 degrees C. Remove the chicken breasts from the marinade, and shake off excess. Discard the remaining marinade. Place the chicken into a baking dish.
Bake the chicken breasts in the preheated oven until no longer pink in the center and the juices run clear, about 45 minutes. Remove from the oven, and allow to cool. Finely slice the chicken and set aside.
To assemble the salad, combine the green cabbage, red cabbage, carrots, 3 spring onions, chopped coriander, almonds and cooled chicken in a large mixing bowl. Pour the reserved dressing over the top and toss the salad to coat.