In a small mixing bowl, whisk together barbecue sauce, soy sauce, rice vinegar, grated ginger, garlic, salt, and pepper.
Transfer chicken to large mixing bowl, toss with half the marinade, then refrigerate for a minimum of 30 minutes or overnight for deeper flavor. Reserve the remaining marinade for cooking.
In a separate large mixing bowl, add red pepper, red onion, pineapple, olive oil, salt, and pepper. Toss until well coated.
Thread chicken, pineapple, red pepper, and red onion onto a skewer; repeat with remaining skewers.
Preheat grill to medium-high heat and brush with oil. Cook skewers 2 to 3 minutes on each side, brushing with reserved marinade as they cook.
Transfer to serving plate and garnish with sesame seeds.