1. Prepare an outdoor grill for medium- high cooking over direct heat. 2. Meanwhile, make the orzo salad: Bring a large saucepan of salted water to a boil over high heat. Add the orzo and cook, stirring often, for about 8 minutes, or until just tender. Drain the orzo in a sieve and set aside. 3. In a medium bowl, whisk the vinegar, shallots, and garlic together. Gradually whisk in the olive oil. Season to taste with salt and pepper. 4. In a large bowl, toss the warm orzo, spinach, tomatoes, pine nuts, and basil with the vinaigrette. Season to taste with salt and pepper. Set aside at room temperature. 5. To cook the salmon: Coat the salmon with olive oil and season with salt and pepper. Oil the cooking grate. Place the salmon on the grill with the top right corner of each fillet facing the 2-o`clock position and cook for 4 minutes, without moving the salmon. (This will help give the salmon a good sear of nice grill marks and help it release from the grate.) Using a thin metal spatula, starting at the corner of each fillet nearest you, flip the fillets over. Grill for about 2 minutes, or until the fish is opaque with a slightly rosy center when flaked in the thickest part with the tip of a small knife. Remove from the grill. 6. Mound the salad in the center of a large serving platter or four dinner plates. Sprinkle with the feta cheese. Top with the salmon, sprinkle with the chives, and serve.