Whisk together first 3 ingredients in a large bowl until smooth; whisk in buttermilk, next 3 ingredients, and 2 tsp. salt until blended.
Place buttermilk mixture and chicken in a large zip-top plastic freezer bag; seal and chill 3 hours.
Meanwhile, soak wooden skewers in water 30 minutes. (Omit if using metal skewers.)
Coat cold cooking grate of grill with cooking spray, and place on grill. Preheat grill to 350° to 400° (medium-high) heat. Remove chicken from marinade, discarding marinade. Thread chicken onto skewers, leaving a 1/8-inch space between pieces; sprinkle with remaining 1/4 tsp. salt.
Grill kabobs, covered with grill lid, 6 to 8 minutes on each side or until chicken is done. Serve with lemon halves and Toasted Pecan Pesto or Romesco Sauce.
Made this dish and served it with the Romesco Sauce. It was delicious. Added white rice which was a great idea. The only problem I had was threading the gooey marinated chicken pieces onto the skewers. Very messy and not an easy task. Would I make this dish again, YES!!!!