In a mixing bowl, combine soy sauce, brown sugar, vegetable oil, lime juice, minced garlic, grated ginger, ground coriander, ground cumin, turmeric, and black pepper. Whisk until well combined.

Add the cubed chicken thighs to the marinade, ensuring each piece is well coated. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes, or up to 2 hours for deeper flavor.

In a separate bowl, combine creamy peanut butter, coconut milk, soy sauce, lime juice, brown sugar, minced garlic, and red pepper flakes.

Whisk the ingredients together until smooth. If the sauce is too thick, add water a tablespoon at a time until the desired consistency is reached. Taste and adjust seasoning if necessary.

Preheat your grill or grill pan over medium-high heat. If using wooden skewers, ensure they have been soaked in water for at least 30 minutes to prevent burning.

Thread the marinated chicken pieces onto the skewers, leaving a little space between each piece for even cooking.

Place the skewers on the grill and cook for about 5-7 minutes on each side, or until the chicken is cooked through and has nice grill marks. The internal temperature should reach 165°F (75°C).

Remove the skewers from the grill and let them rest for a few minutes.

Serve the chicken satay with the peanut sauce on the side for dipping. Garnish with chopped cilantro or crushed peanuts if desired.