Wash, dry, and cut in half the radicchio and slice it very thinly. Arrange it in the center of the serving dishes. Cut and discard the green part of the fennel, keeping the fine green leaves for garnishing. Wash the white part and slice it thinly. Arrange it around the radicchio.
Peel the orange with a sharp knife, removing also all the white skin. Pull out the sections from in-between the skin and arrange them on the radicchio. Garnish your salad with the fennel green leaves. In a small bowl, mix the balsamic vinegar, EVOO and salt; pour a couple of tablespoons on each salad.