Cut the chicken into 2cm chunks.
Mix the marinade ingredients in a large bowl. Add the chicken, cover and set aside in the fridge for at least 4 hours.
Heat your grill element or fire up your BBQ, slice your red onion into rough slices.
Stick the chicken pieces onto skewers, putting a few couple of slices of red onion between each piece of chicken. If using wooden skewers, soak them first in water to prevent them from burning during cooking.
Cook the skewers for 10-12 minute, turning every 2-3 minutes. You want the chicken to have charred a bit without drying out inside. You should definitely still have some juice in there!