To make the choi sum: Toss the choi sum leaves, sugar snap peas, carrots, red bell pepper, yellow bell pepper, pineapple, and spring onions together in a large serving bowl. To make the dressing: Mix the groundnut oil, pineapple juice, light soy sauce, rice vinegar, and black pepper in a small bowl, and stir well. Then, pour the dressing mixture over the salad just before serving. Toss well, and serve immediately.
Recipe courtesy of Ching-He Huang, 2008