Preheat oven 425 degrees F. Place salmon in a baking dish. Drizzle with olive oil, orange juice, and lemon juice. Sprinkle with chopped dill and salt and pepper. Bake 15 minutes, or until salmon is cooked through. Divide and pile the spinach on the four plates. Top the spinach with a piece of salmon. Spoon the pan juices over top. Garnish with dill and citrus slices.
If desired, serve salmon with boiled new potatoes and steamed carrots.