Whisk together the lemon juice, lime juice, cider vinegar, salt and pepper in a large bowl. Add the chicken and toss to evenly coat. Cover the bowl with glad wrap then marinate in the refrigerator for 1 hour.
Preheat an barbecue for medium-high heat then lightly oil the grate.
Remove the chicken from the marinade then shake off excess. Discard the remaining marinade. Barbecue the chicken for 5 to 7 minutes each side or until juices run clear when chicken is pierced with a fork. Barbecue pineapple for 2 to 3 minutes per side or until heated through and BBQ marks appear.
Spread 1 teaspoon teriyaki sauce on the bottom half of a toasted roll; next add a lettuce leaf, a piece of chicken, a pineapple round and an onion slice. Replace the top and repeat with the remaining rolls.