Pat the chicken dry with paper towels. Score both sides of each piece (about 1/4 inch deep is ideal). Place in a wide shallow bowl.
In a mixing bowl, stir together the soy sauce, salt, lemon juice, pineapple juice, ginger, garlic, chilies and Worcestershire sauce. Pour over the chicken. Mix well. Cover the bowl and marinate the chicken in the fridge for at least six hours (overnight is better).
Heat the grill. Position the rack at least six inches from the heat (if the rack is too near the heat, the chicken will scorch before the inside is thoroughly cooked).
Drain the chicken.
Make the basting sauce. Pour the leftover marinade in a mixing bowl and stir in the sugar and ketchup. Make sure that the sugar is completely dissolved.
Grill the chicken, about five minutes per side. Brush with the basting sauce several times during grilling.
Take the cooked huli huli chicken off the grill. Brush each piece lightly with sesame seed oil. Serve at once.