Sauté onion in hot oil in a large nonstick skillet over medium-high heat 5 minutes or until tender. Add squash, and cook 1 to 2 minutes or just until warm. Remove from heat.
Toss spinach in a bowl with Blue Cheese Vinaigrette. Arrange baby spinach on a serving platter; top with squash mixture, cranberries, pecans, and bacon.
Note: Nutritional analysis does not include dressing.