Salad greens should be crisp, with firm outer leaves. They should also smell sweet, not bitter, for the freshest dish.
For the dressing: in a blender, combine juice, honey, shallot, and vinegar. Season with salt and pepper. Blend until smooth. With motor running, add oil in a steady stream until emulsified.
In a large bowl, toss arugula, frisee, and radicchio with dressing; season with more salt and pepper. Serve immediately.