In a small frying pan toast the coriander, cumin, and fennel seeds over medium heat until fragrant, occasionally shaking the pan. Grind into a fine powder; set aside.
Process the onion, garlic, lemongrass, galangal, ginger, salt, and palm sugar until a smooth paste.
In a large bowl add the ground spices, onion paste, vinegar, and turmeric; stir until well combined.
Add the chicken to the marinade in the bowl and stir to coat. Chill to marinate for at least 4 hours, stirring occasionally.
Chicken Satay
Preheat a grill for direct cooking over high heat.
Thread the chicken onto the bamboo skewers leaving a good portion to hold while eating.
Place the satay skewers over the grill with the meat over the direct heat and the handles in a cooler area or even outside the grill.
Cook while brushing with coconut milk, turning continually, to keep the meat moist.
Serve hot with sliced cucumbers, satay sauce, or your favorite accompaniment.