Preheat grill to medium heat.
Evenly cut the pineapple into 1/2-inch thick slices. Using a small 1-inch biscuit cutter, pierce a hole into middle of pineapple slices. Brush the pineapple and onion slices with glaze, place on the grill and brush again with glaze. Grill for 2 minutes and flip, grilling other side.
Place a bed of spinach leaves on a serving platter and top with the pineapple and onion slices. Drizzle with Vinaigrette and serve.
Place all ingredients into a medium bowl and whisk together.
Pour ingredients into a small bowl and whisk together.