Slice the head of radicchio into thin slices. Cut endive into rounds. Remove stems from arugula. Wash under cold water and spin dry.
In a large bowl toss all the greens together. Season with salt and pepper. Drizzle with Citrus Vinaigrette (see recipe below).
In a small bowl combine juices and mustard. Slowly drizzle in olive oil while whisking. Season with salt and pepper.
Yield: about 1/2 cup dressing