Soak eight 12-inch long skewers in water, if made of wood/bamboo. Set aside while you prepare the recipe.
Cut the pineapple, onion, and chicken thighs into roughly 1-inch cubes, and keep them separate in three bowls or containers. Set aside.
In a small bowl, combine the Colavita Extra Virgin Olive Oil and Balsamic Glaze, pepper, salt, and oregano, stirring until well-blended. Pour marinade over the chicken thighs and allow to sit, covered, for at least 15-20 minutes, and up to 8 hours.
Preheat the grill to high for 15 minutes. If you do not have a grill, preheat a broiler to high with the oven rack in the upper third of the oven. While preheating, create the skewers by alternating pieces of marinated chicken, pineapple, and onion, leaving space at the top and bottom for easy holding. Approximately 4 pieces each of chicken, pineapple, and onion should fit on a 12-inch skewer.
Brush skewers with remaining marinade, and arrange on a grill grate sprayed with Colavita Avocado Oil Spray. If using the broiler, use an oil-sprayed wire rack set inside a half sheet pan. Cook skewers on each side until charred and sizzling, approximately 10-12 minutes total. Season with additional freshly ground black pepper and salt to taste, and serve immediately.