If using wooden skewers, soak them in water for 20–30 minutes. Cut the chicken into 1-inch pieces.
Make the marinade: In a bowl, whisk 4 tbsp soy sauce, 2 tbsp lime juice, 1 tbsp brown sugar, fish sauce, 3 minced garlic cloves, grated ginger, ground coriander, ground turmeric, and 2 tbsp vegetable oil until combined.
Add the chicken to the marinade, toss to coat, cover, and refrigerate 30 minutes to 2 hours (1 hour ideal), stirring once midway.
Make the peanut sauce: In a small bowl, whisk peanut butter, coconut milk, remaining 1 tbsp soy sauce, remaining 1 tbsp lime juice, remaining 1 tbsp brown sugar, sriracha, and the remaining 1 minced garlic clove until smooth. Whisk in 1–2 tbsp water to reach a pourable, dipping-sauce consistency. Divide the sauce: set aside half for basting and the rest for serving.
Thread the marinated chicken onto soaked skewers, packing pieces snugly but not tight. Discard any excess marinade.
Preheat a grill to medium-high heat (400–450°F). Clean the grates, then oil them with the remaining 1 tbsp vegetable oil using tongs and a paper towel.
Grill the kabobs, turning every 2–3 minutes, until nicely charred and the chicken reaches 165°F, 8–12 minutes total. During the last 2 minutes, brush lightly with some of the reserved basting peanut sauce to glaze, avoiding flare-ups.
Transfer kabobs to a platter and rest 5 minutes. Serve with the remaining peanut sauce for dipping, sprinkle with chopped roasted peanuts and cilantro, and offer lime wedges for squeezing.