Grilled Salmon and Spinach Salad

"This dish is perfect for summer. It is also an attractive dish to serve to guests. Sweet citrus vinaigrette can be prepared earlier in the day and stored in the refrigerator. " - Arlene Gent, New Haven, Conn.
Preheat the grill to medium-high heat.To make the vinaigrette, combine the first 6 ingredients in a large bowl; mix well with a whisk.To make the salad, drizzle the fillet with lemon juice; sprinkle with 2 teaspoons of pepper. Place the fillets, skin side up, on a grill rack greased with cooking spray; cook for 5 minutes on each side, or until the fish flakes easily when pricked with a fork, or until the desired degree of roasting is achieved. Remove the skin from the fillet; discard.Add the spinach to the vinaigrette in the bowl; mix well. Place 2 cups of the spinach mixture on each of the 4 serving plates; arrange 1 fillet and 6 orange slices on top of the greens.