Cut the chicken breast into 2 cm wide strips and place on wooden skewers like an accordion. Place in a deep plate.
Put the garlic, onion, half of each of the sugars and the fish sauce in a blender to make a paste, then dilute slightly with cold water. Pour this paste over the meat and cover with cling film. Marinate for approx. 3 - 4 hours.
Boil the remaining ingredients in a saucepan over medium heat for about 4 minutes to a thick sauce.
Brush the meat skewers with oil and grill them brown on a hot wood grill or in a hot pan. Brush with oil every now and then.
Arrange the finished skewers in a fan shape on a plate and serve the sauce in a bowl.
Another note about the quantities: this makes about 12 skewers. Depending on whether you use it as a starter or main course, more or fewer people can eat it.