In a large mixing bowl, combine all of the satay chicken ingredients until everything is evenly distributed and the chicken is fully coated. Cover and marinate in the fridge for 1 hour.
Now is a good time to soak your skewers in water if they are bamboo/wooden. You can also dry toast the peanuts in a pan over medium heat until lightly charred, then finely crush in a pestle and mortar or food processor.
Once the chicken has marinated, thread it onto the skewers, ensuring you leave a gap at both ends. Add a drizzle of oil to a large pan over medium heat. Working in batches and topping up with oil in between, add the skewers to the pan and fry for 3-4 mins each side, or until lightly charred on the outside and piping hot through the centre (safe internal temp 74C/165F). I like to baste the cooked side of the skewers in coconut milk, just to keep them juicy. Also, just be careful the chicken doesn't stick to the pan (you can keep peeking to check).
For the sauce, place a medium-sized pot over low-medium heat, then add the oil. Add the massaman paste and fry for 30 seconds or so until fragrant (be careful it doesn't burn). Add the coconut milk, tamarind and sugar and keep on a gentle simmer for a few minutes, or until it starts to thicken. Stir in the crushed peanuts, then remove from the heat. You can continue simmering to thicken if needed, but keep in mind the sauce will thicken more as it rests.
Pour the sauce into a small serving bowl, stack the skewers, then tuck in and enjoy!