Place the chicken tenderloins into a large zip-top bag or container.
In a mixing bowl, whisk together 1/2 cup creamy peanut butter, coconut milk, brown sugar, soy sauce, the zest and juice of 1 lime, and 1/4 teaspoon salt until smooth.
Pour the marinade into the bag with the chicken, seal, and refrigerate for 2–4 hours (or up to the 2 hours indicated in prep time).
Soak wooden skewers in water for at least 10 minutes to prevent burning, then thread the marinated chicken onto the skewers.
Preheat a grill or grill pan to medium heat.
Grill the skewered chicken 3–4 minutes per side, turning once, until an instant-read thermometer inserted into the thickest part reads 165°F (74°C).
For the dipping sauce, place 1/2 cup peanut butter in a small microwave-safe bowl and heat 10–15 seconds to soften, or warm gently in a small saucepan.
Stir in 3 tablespoons hoisin sauce, 1 teaspoon sriracha, 1 tablespoon lime juice and 1 tablespoon water. Add more water, up to 2–3 tablespoons total, to reach desired consistency.
Serve the grilled chicken skewers garnished with chopped cilantro, with the peanut dipping sauce on the side.