1. Preheat grill to medium-high heat.
2. To prepare chicken, combine first 6 ingredients; rub evenly over chicken. Place chicken on a grill rack coated with cooking spray; cover and grill 15 minutes or until a thermometer registers 180°, turning occasionally. Let stand for 5 minutes. Shred with 2 forks.
3. To prepare sauce, while chicken grills, heat canola oil in a medium saucepan over medium heat. Add onion; cook for 5 minutes or until tender, stirring occasionally. Stir in 1 tablespoon sugar and next 5 ingredients (through ground red pepper); cook 30 seconds. Stir in ketchup and vinegar; bring to a boil. Reduce heat, and simmer 10 minutes or until slightly thickened, stirring occasionally. Stir in chicken; cook 2 minutes.
4. Place 1/3 cup chicken mixture on bottom half of each bun; top each with 2 pickle chips and top of bun.