If using wooden skewers, soak for 30 minutes (no need to worry if using metal).
To make the marinade, blend the garlic, coriander, turmeric, chilli powder, sugar, lime juice and soy together in a food processor.
Cut the chicken into 1 cm (½ inch) or less slices. Place in a shallow ceramic or glass baking dish or zip lock bag. Pour the marinade over the chicken and massage into the meat. Refrigerate for 1 hour or up to overnight. Thread the slices onto the wooden or metal skewers.
To make the peanut sauce, in a food processor purée the roasted peanuts with 60 ml (2 fl oz) water and pulse until very fine.
Heat the oil in a medium saucepan. Add the garlic and cook over a low heat for 2 minutes, stirring often, until golden. Add the remaining peanut sauce ingredients along with the peanuts. If the sauce is too thick, then add a little more water. Sauté over medium heat for 10 minutes and then remove and pour into a serving bowl.
Preheat your outdoor grill or a chargrill pan. Drain the chicken, brush with oil and cook on direct medium heat or, if using charcoal, cook on direct heat when the coals have died down a bit. Grill for 2–3 minutes.
Serve the satay with the peanut sauce, cucumber and onion wedges. You can also add some steamed or sticky rice to bulk it out.