Lay the konnyaku cake on a cutting board lengthwise, then cut into quarters. Then halve the konnyaku slices crosswise to make them thinner. Cut the onion across the grain into 4 pieces. Cut the bell peppers and piman green pepper into 4 slices. Preheat the oven to 480°F.
Thread the konnyaku, bell pepper, onion, and piman green pepper slices onto metal kebab skewers, alternating between ingredients for a colorful kebab.
Cover a baking sheet with parchment paper and arrange the kebabs on the sheet so that they are not touching. Drizzle with olive oil, then place in the oven for approx. 12 minutes until thoroughly cooked.
Mix together ketchup, Worcestershire sauce, lemon juice, Dynasty sriracha chili sauce, honey, soy sauce, and grated garlic. Plate the kebabs and brush with the sriracha barbecue sauce.