Combine all huli huli sauce ingredients in a large mixing bowl and whisk together thoroughly. Set aside one cup of sauce in the refrigerator for glazing. Then, slice pineapple into ¼” slices.
Cut chicken filets in half, separating the thick and thin portions, and place them in a sealable plastic bag. Pour sauce over chicken and place in the refrigerator for 4-6 hours.
Light grill and set up for two zone heat. Take reserved marinade out of the refrigerator and allow it to come up to room temperature as your grill heats up.
Remove chicken from plastic bag, and discard remaining marinade. Place the chicken and pineapple slices on the grill over direct heat. Flip them every two minutes until the pineapple is charred and the internal temperature of the chicken reaches 155°F as indicated by a reliable quick read thermometer. Remove the chicken as the individual pieces reach target temperature, and when pineapple is charred.
Return the chicken to the indirect heat side of the grill and glaze with sauce that was set aside. Close lid and allow to roast for five minutes or until temperature reaches 170°F.
Plate, garnish with sliced green onions and serve immediately.