In a shallow large bowl, whisk water, soy sauce, vinegar, ginger, garlic, honey, brown sugar, and cornstarch mixture.
Arrange chicken in marinade bowl and turn to evenly coat. Allow chicken to marinate 2 hours or up to 12.
Preheat an outdoor grill to medium-high heat OR prepare a large skillet to use indoors on stovetop by greasing well. Remove chicken from marinade and pat dry (do not discard marinade).
Arrange chicken and pineapple on grill or on stovetop, turning occasionally until pineapple is charred and chicken registers 165F (cook chicken and pineapple in batches if cooking on stovetop adding additional oil as needed for pan)
Pour teriyaki marinade into a small pan and bring to a simmer over medium heat. Reduce heat to medium-low and allow to simmer 5 minutes, stirring occasionally. Set aside for a moment.
Arrange grilled chicken and pineapple on a serving plate and brush with teriyaki sauce. Top chicken with green onions and serve warm with rice. Enjoy!