How to Make It
In a large saucepan of salted boiling water, cook the orzo until al dente; drain and transfer to a large bowl.
Meanwhile, in a small bowl, soak the bread in the vinegar. In a small skillet, toast the coriander seeds, stirring, until fragrant, 2 minutes. Transfer the seeds to a mortar. Add the garlic and 1/2 teaspoon of salt and pound with a pestle until a paste forms. One at a time, pound in the capers, almonds, scallions, fennel fronds and olives, until the mixture is chunky. Pound in the soaked bread, then pound in the olive oil, 2 tablespoons at a time.
Add the dressing and radicchio to the orzo, season with salt and toss well.
You can finely chop the fennel bulb and add it to the orzo as well, if desired.