Pat the chicken pieces completely dry with paper towels and season generously with salt and pepper.
Heat oil in a large skillet over medium-high heat. Once shimmering, add the chicken in a single layer, working in batches if necessary to avoid overcrowding. Sear for 3-4 minutes per side, until deeply golden brown. Remove the chicken to a plate.
Lower the heat to medium. Add the minced garlic and ginger to the skillet and sauté for 30-60 seconds until fragrant, stirring constantly.
Carefully pour in the bourbon to deglaze the pan, scraping up any browned bits from the bottom with a wooden spoon. Let it bubble for 1 minute.
Drain the juice from the can of pineapple into the skillet. Set the pineapple chunks aside. Add the pineapple juice, soy sauce, brown sugar, and rice vinegar to the pan. Whisk until the sugar dissolves and bring to a simmer.
Let the sauce simmer for 5-7 minutes to reduce slightly. In a small bowl, whisk together the cornstarch and cold water to create a smooth slurry. Slowly pour the slurry into the simmering sauce while whisking constantly. Cook for 1-2 minutes until the sauce thickens and becomes glossy.
Return the seared chicken and any accumulated juices back to the skillet. Add the reserved pineapple chunks. Stir to coat everything in the glaze.
Simmer for another 3-5 minutes, until the chicken is cooked through and the sauce is clinging to every piece. If desired, stir in the optional toasted sesame oil.
Serve immediately over fluffy rice, garnished with sliced green onions and toasted sesame seeds.