1. In colander, toss cabbage and kohlrabi with 1/2 teaspoon salt. Let sit for 1 hour (this will allow cabbage and kohlrabi to release excess water). Rinse cabbage and kohlrabi thoroughly in cold water and pat dry with towel or paper towels.
2. Combine rice vinegar, wasabi powder, sugar, water soy sauce and garlic in small bowl. Whisk to blend completely.
3. Add cabbage, kohlrabi, red bell pepper and scallions to large bowl. Pour dressing over vegetables. Toss gently to coat evenly.
4. Cover and chill for 4 hours before serving. Garnish with parsley sprigs. Serves 4..