PLACE dressing ingredients in small covered container; shake well to blend. Refrigerate until ready to serve.
PLACE spinach, blueberries, red onion and walnuts in serving bowl. Drizzle with dressing; toss lightly. Sprinkle with cheese.
To caramelize walnuts, heat 3 tablespoons sugar in medium skillet over medium-high heat until sugar begins to melt. Add 1/2 cup coarsely chopped walnuts; stir constantly until sugar is melted and nuts are coated. Turn onto waxed paper; cool completely.