Freshly chopped cilantro for garnish, lime slices for garnish, and soft corn tortillas
Make the Chicken: In a large bowl, whisk together the onion, garlic, ginger, pineapple juice, soy sauce, sugar, vinegar, and Asian sesame oil. Whisk until sugar is dissolved and marinade is well incorporated.
Use paper towels to thoroughly pat-dry the chicken pieces. Place chicken in a single layer on a cutting board, place a sheet of cling wrap over the chicken, and pound to an even thickness. Throw out cling wrap. Use a fork to pierce chicken pieces throughout. Lightly sprinkle chicken thighs on both sides with table salt. Toss chicken in bowl of marinade to coat well. Cover and chill overnight, or up to 2 nights. Be sure to turn chicken pieces over halfway through, if all pieces aren't completely immersed in marinade.
Make the Hawaiian Salsa: Combine all salsa ingredients in a bowl, toss well, and let chill until ready to use.
To Serve: Grease and heat outdoor grill (or indoor grill pan) to medium-high. Remove chicken from marinade and grill (basting with marinade as desired) just until center is no longer pink, taking care not to over-cook. Discard marinade. Let chicken rest 5 minutes, then slice.
Serve chicken and salsa with soft corn tortillas, garnished as desired.