To prepare chicken: Whisk 3 tablespoons lime juice, oil, 2 teaspoons soy sauce, fish sauce and ½ teaspoon red pepper in a shallow dish until combined; add chicken and turn to coat. Let marinate in the refrigerator for 15 minutes.
To prepare peanut sauce: Whisk peanut butter, coconut milk, lime juice, soy sauce, brown sugar and red pepper until smooth.
Preheat grill to high. Thread each chicken tender onto a wooden skewer. Grill until cooked through and no longer pink in the middle, about 3 minutes per side. Serve warm or chilled with Spicy Peanut Sauce.
