PROCESS vinaigrette, onions, soy sauce, chiles, garlic and seasonings in food processor until well blended. Pour over chicken in non-reactive pan; turn to coat both sides of each piece. Refrigerate at least 6 hours or up to 24 hours to marinate.
REMOVE chicken from marinade; discard marinade. Grill chicken on medium heat until done (165ºF), turning occasionally. Remove skin and bones from chicken; discard. Shred meat. Refrigerate until ready to use.
CARAMELIZED-PINEAPPLE Relish: Heat large skillet on medium-high heat. Add sugar and lemon juice; cook and stir 1 to 2 min. or until sugar is completely melted and golden brown. Add pineapple; cook and stir 4 to 5 min. or until tender. Use slotted spoon to transfer pineapple from skillet to bowl. Cook liquid remaining in skillet until reduced to about 1/2 cup (or to about 1/4 cup for trial recipe). Pour over pineapple; mix lightly. Refrigerate until ready to use.
FOR each serving: Spoon about 1 Tbsp. Caramelized-Pineapple Relish onto each of 2 Black Sesame Crackers; top each with about 3/4 oz. chicken.