Combine the first 4 ingredients, tossing well to coat. Place hazelnut mixture on a nonstick baking sheet coated with cooking spray; bake at 350° for 6 minutes or until lightly browned. Remove from oven; cool.
Combine juice and next 4 ingredients (juice through pepper), stirring well with a whisk. Place the spinach in a large bowl; drizzle with juice mixture. Toss gently to coat. Place about 1 3/4 cups salad mixture on each of 4 plates; top with 1/4 cup orange sections and 1 tablespoon hazelnut mixture.