Cut chicken into 2-inch pieces. In a bowl, whisk together soy sauce, brown sugar, lemon juice, garlic and ginger. Add sauce and chicken to a bag and store in the refrigerator to marinate for 2 or more hours.
Soak 16 skewers in water for 30 minutes.
Make the chili sauce. In a small bowl, combine cornstarch with 1 Tbsp water until dissolved. In a saucepan, combine ⅓ cup water with chili sauce, rice vinegar, and garlic powder. Bring to a boil and cook until sauce is smooth. Whisk in cornstarch. Continue whisking quickly until sauce is thick. Set aside to cool.
Once chicken is done marinating, cut fresh pineapple into cubes – ensuring that one side is no thicker than the thickness of the chicken pieces.
Remove chicken from the bag and alternate placing chicken and pineapple cubes onto skewer.
Heat a pan on medium-high heat with oil. Add skewers and cook for about 4 to 6 minutes, rotating every few minutes, until chicken is cooked through.