1. preheat oven to 400 degrees. Wrap each sweet potato in foil and bake for 2 hour. Unwrap; let cool. Peel, cut into 3/4-inch chunks. 2. In a large bowl, mix mayonnaise and mustard. Add sweet potatoes, celery, red pepper, pineapple and scallions, toss gently. Season to taste with walt and peper. Cover and refrigerate about 1 hout. 3. Fold in pecans and sprinkle with chives. 114 calories per serving.