1. In a bowl, mix chicken with soy sauce, lime juice, garlic, coriander, and cumin. Marinate for at least 30 minutes.
2. Thread marinated chicken onto skewers.
3. Grill the skewers over medium heat for about 10 minutes, turning occasionally, until cooked through.
4. For the peanut sauce, combine peanut butter, coconut milk, soy sauce, lime juice, brown sugar, and garlic in a saucepan. Cook over low heat until smooth and heated through.
5. Serve the chicken skewers with peanut sauce on the side.