To make dressing, squeeze juice from limes into a bowl. Stir in soy, sugar, ginger, fish sauce, garlic and chili flakes.
For salad, cut pepper into thin strips. Cut cucumber in half lengthwise. Using a spoon, scrape out seeds. Thinly slice cucumber. Slice cabbage into thin strips. Chop coriander. Place all in a large bowl along with spinach. Toss to evenly mix.
Trim fat from chicken. Slice chicken into thin strips. Lightly coat a large frying pan with oil and set over medium-high heat. Add chicken. Sprinkle with salt. Stir often until chicken begins to lose its pink colour, 2 to 3 minutes. Pour in dressing. Stir often until chicken is cooked through, 3 minutes. Pour over salad and toss to evenly mix. Great topped with chopped mango and peanuts.