Spoon 1 tablespoon cream cheese in center of each slice of bread, spreading to the top and bottom, leaving a 3/4-inch border on sides. Layer half of bread slices with radish slices, overlapping slightly.
Sprinkle lightly with salt and pepper; top with lettuce and remaining bread slices (cream cheese side down) to make 4 sandwiches. With a serrated knife, trim off crusts; cut each sandwich in half. Serve.