This dish can be prepared a day ahead of time. It won't hurt the chicken to marinate longer. Then just fire up the grill and they'll be done in 15 minutes. This recipe was adapted from Bon Appetit.
Cut each breast into cubes about 1-to-1.5-inch square. Transfer chicken breasts to a resealable plastic bag.
Combine the remaining ingredients in a food processor and blend until smooth. Poor yogurt mixture over chicken, seal bag and turn to coat. Marinate chicken in the refrigerator for at least three hours or overnight.
Scrape excess marinade off chicken and place 6-8 chicken squares on wooden or metal skewers about 1/2 inch apart. Season with salt.
Heat gas grill to medium high. Brush grill gates with oil. Grill chicken until browned and cooked through, turning a few times. About 6-8 minutes total.