First, segment oranges: Cut off very top and bottom of orange (the orange will sit flat). Remove skin and bitter pith of orange by hand or with a knife. Using a small knife, cut out each segment of the orange, leaving behind the membrane. Segment the orange over bowl to collect juice!
Next, prepare radishes. Wash well, scrub if necessary, then coarsely grate. Combine radishes, orange segments and juice, add a little salt and pepper, and toss. Refrigerate a few hours. Sprinkle with finely diced walnuts and chopped herbs, drizzle with olive oil, serve!