Place the salmon, cream cheese, scallions, lemon juice, horseradish, dill and pepper in a food processor. Process until the mixture is smooth and well blended (stop the machine occasionally to scrape down the sides). Spoon the contents into a serving bowl and refrigerate for at least 2 hours. Use as a spread with crackers, matzo or crudites. If desired decorate the top with a sprig of fresh dill, halved grape tomatoes, lemon slice, etc.