You might not have tried the combination of sweet potato (kumara) and pineapple but it's a tropical sensation! Serve this with a spicy meal to balance the hotness.
Cook diced sweet potatoes in salted boiling water until just tender, about 10 minutes. Drain and put in a salad bowl.
In a small bowl, combine the drained pineapple juice, oil, soy, vinegar and red pepper. Pour over the sweet potatoes. Add pineapple pieces, water chestnuts, red onion and spring onions. Toss and serve.