In a small bowl, blend together the mascarpone and cream cheese until smooth. Divide the cheese among the tortillas evenly and spread covering the tortillas. Lay the salmon slices on top of the cheese down the center of the tortilla. Sprinkle with red onion slices, cucumber, and ground pepper. To make sure there is salmon in every bite, place salmon lengthwise across the tortilla and toll tightly to create a log shape. Wrap in plastic and refrigerate for up to 12 hours. Just before serving, cur the wrap in half crosswise on a slight diagonal. Yield: 4 servings