Step 1: Prepare the chicken. In a medium bowl, combine the chicken pieces with soy sauce, sesame oil, garlic powder, and black pepper. Toss to coat evenly. Let marinate for at least 15 minutes at room temperature, or up to 30 minutes in the refrigerator.
Step 2: While the chicken marinates, prepare the bang bang sauce. In a small bowl, whisk together the mayonnaise, sweet chili sauce, sriracha, honey, rice vinegar, and creamy peanut butter until smooth and well combined. Taste and adjust spice or sweetness if desired.
Step 3: Thread the marinated chicken pieces onto the soaked wooden skewers. Don't pack them too tightly, leaving a small space between each piece for even cooking. You should get about 3-4 pieces per skewer, making 12 skewers in total.
Step 4: Preheat your grill to medium-high heat (about 400°F/200°C). Lightly oil the grill grates to prevent sticking.
Step 5: Place the chicken skewers on the preheated grill. Grill for 3-4 minutes per side, turning occasionally, until the chicken is cooked through and has nice char marks. This typically takes 12-15 minutes total. The internal temperature should reach 165°F (74°C).
Step 6: During the last 2-3 minutes of grilling, generously brush the bang bang sauce over all sides of the chicken skewers. Allow the sauce to caramelize slightly, being careful not to burn it due to the sugars.
Step 7: Alternatively, for baking: Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper. Arrange skewers in a single layer. Bake for 15-20 minutes, flipping halfway, until chicken is cooked through. Brush with sauce during the last 5-7 minutes of baking.
Step 8: Remove the bang bang chicken skewers from the grill or oven. Let them rest for a few minutes before serving.
Step 9: Garnish with sesame seeds and chopped green onions, and serve hot with any remaining bang bang sauce on the side for dipping.