1. Cut the bacon slices into 1/2-inch pieces and fry in a skillet until well browned. Drain on paper towels. 2. Combine the bacon, sweet potatoes and pineapple in a large mixing bowl and toss lightly. In a small bowl conbine the mayonnaise, mustard, lime juice and pepper. 3. Add dressing to the potato mixture and mix lightly but thoroughly. Just before serving, stir in the macadamia nuts. 4. Serve the salad in a chilled salad bowl lined with romaine leaves.