Cut chicken wings into three sections at each joint and discard tips.
In a bowl, combine onion, Worcestershire sauce, red pepper flakes, maple syrup, chili sauce, and Dijon mustard. Reserve 1 cup of glaze for basting and refrigerate.
Place chicken into a ZipLoc bag and pour remaining glaze over them. Turn chicken until evenly coated.
Place bag in a large bowl to contain possible leaks and refrigerate for 4 hours, turning occasionally. Drain chicken and discard excess marinade.
Grill chicken, covered, over medium heat for 12 to 16 minutes, turning occasionally. Then brush with reserved marinade and grill, covered, for another 8 to 10 minutes or until juices run clear, basting and turning several times.