For dressing, in a screw-top jar combine the orange juice, olive oil, vinegar, mustard, marmalade, salt, and pepper. Cover and shake well. Set dressing aside.
Slice avocados. Fan avocado slices over shredded spinach on each of 6 salad plates. Top each with salmon and shredded radish. Shake dressing; drizzle over each salad or pass separately. Garnish each serving with 2 chives. Makes 6 servings.