In a bowl, whisk together the pineapple juice, soy sauce, rice wine vinegar, brown sugar, pressed garlic, grated ginger, and sesame oil until the sugar dissolves completely. This balanced marinade combines sweet, salty, and umami flavors that will deeply penetrate the chicken. Place the cut chicken thighs into a large zip-top bag or shallow container, pour the marinade over them, seal, and refrigerate for at least 2 hours but preferably overnight—this time allows the marinade to tenderize the chicken and infuse it with flavor. I find that marinating overnight gives the chicken a noticeably deeper, more complex taste compared to just 2 hours.

While the chicken marinates, prepare the remaining components. Core and cut the fresh pineapple into 1-inch chunks, keeping them separate from the marinade. Thinly slice the large onion and set aside—the onion will be used both for the reduced sauce glaze and can be grilled alongside the skewers if desired for added caramelization and flavor.

About 30 minutes before grilling, remove the chicken from the marinade and let it come closer to room temperature—this ensures more even cooking. Reserve the marinade in a separate pot for the sauce. Thread the marinated chicken and pineapple chunks onto metal or soaked wooden skewers, alternating pieces to create visual appeal and ensure even heat distribution. Preheat your grill to medium-high heat (around 400°F) and lightly coat the grill grates with cooking oil spray to prevent sticking.

While the grill heats, pour the reserved marinade into a saucepan and bring it to a rolling boil over medium-high heat. Let it reduce for 8-10 minutes, stirring occasionally, until it's reduced by approximately half and becomes glossy and syrupy. This concentrated sauce will caramelize beautifully on the skewers and add a rich, intense flavor. I like to add the sliced onion to this reducing sauce—it softens and becomes part of the glaze, adding natural sweetness and texture.

Place the assembled skewers on the preheated grill and cook for 4-5 minutes per side, rotating a quarter turn each time to create attractive grill marks and ensure even cooking. After the first rotation, begin brushing the reduced marinade glaze onto the skewers with a pastry brush, reapplying it after each turn for a beautiful caramelized coating. Continue grilling and turning until the chicken reaches an internal temperature of 165°F (about 15-20 minutes total depending on skewer thickness), the exterior is lightly charred, and the pineapple has developed golden caramelization.

Transfer the grilled skewers to a serving platter and let them rest for 3-5 minutes before serving. This short rest allows the juices to redistribute throughout the chicken, keeping it moist and tender. Serve immediately while the skewers are still warm and the glaze is sticky.