In a small bowl, combine the lime juice, brown sugar, ginger, fish sauce, chile paste and garlic stirring well with a whisk.
Over medium high heat, heat a large non-stick skillet or a grill pan coated with cooking spray. Rub both sides of the steak with pepper. Add steak to pan and cook six minutes on each side or until desired degree of doneness. Remove from pan, cover loosely with foil and let stand five minutes to cool. Cut steak diagonally across the grain into thin slices. Place steak in a bowl. Drizzle with half of the dressing and toss well.
In a large bowl, combine watercress, red cabbage, basil, mint, cilantro and carrots. Drizzle with remaining dressing and toss well. Divide salad evenly among six plates; arrange steak evenly over salad and serve. (Optional: Before serving, sprinkle each serving with a teaspoon of peanuts.)