How to Make It
Preheat the oven to 450°. In a nonreactive bowl, combine the orange juice, balsamic vinegar, extra-virgin olive oil, onion, anchovy, orange zest and fresh herbs. Season with salt and pepper. Place the spinach, fennel and radicchio in a heatproof bowl.
In a large nonreactive ovenproof skillet, heat the pure olive oil. Season the salmon fillets with salt and pepper and add them to the skillet, skinned side down. Cook over high heat for 1 minute. Transfer the skillet to the oven and roast the salmon until just cooked through, about 6 minutes. Remove to a plate.
Wipe out the skillet and add the reserved dressing. Bring to a simmer over high heat, then pour the hot dressing over the greens and toss to mix. Arrange the slightly wilted greens on 4 plates, set a piece of salmon on top and serve.