Combine all of the glaze ingredients in a bowl, whisk well to combine, reserve 2 tablespoons of the glaze in a separate bowl and set aside. Add the cut apples and red onion to a mixing bowl, add half of the glaze and toss well to coat the chunks evenly. Add the cut chicken to a separate bowl and combine well with the remaining glaze.
Heat a grill on medium high heat. Load the skewers with some chicken, apple and onion chunks, taking care not to pack them on too tightly, and transfer to a plate. Grill the skewers, turning once, until the chicken is cooked through (test by cutting through a piece to check for doneness, or the internal temperature of the chicken should be 160 degrees Fahrenheit).
Remove skewers onto a clean plate and brush or drizzle with the remaining 2 tablespoons of glaze. Serve immediately.
Leftover skewers can be refrigerated in an airtight container for up to 2 days.