Sweet and Sour Chicken Skewers

Name: Sweet-and-Sour Chicken Skewers
Ingredients: 1 lb boneless, skinless chicken breast, cut into bite-size chunks; 2 medium zucchini, cut into large chunks; 2 cups large pineapple chunks, drained; 1 tbsp maple syrup; 2 medium red onions, cut into large chunks; 2 red bell peppers, cut into large chunks; 8 wooden skewers, soaked in cold water for 20 minutes; salt and black pepper; 3 tbsp ketchup; 1/2 tbsp soy sauce; 1 tbsp vinegar (rice wine or cider); 1 tsp sriracha hot sauce; Fresh chopped cilantro (optional)