In a large bowl, combine soy sauce, banana ketchup, brown sugar, white vinegar, minced garlic, chopped onion, ground black pepper, salt, paprika, and water. Whisk until well combined.

Add bite-sized pieces of chicken to the marinade and ensure they are evenly coated. Cover and refrigerate for at least 2 hours, preferably overnight.

Preheat your grill or grill pan to medium-high heat (around 400°F).

Remove marinated chicken from the refrigerator and thread pieces onto soaked bamboo skewers, leaving space between them.

Place skewers on the preheated grill and cook for 5-7 minutes per side, basting with reserved marinade.

Once grilled, remove from heat and let rest for a few minutes before serving.