Dice chicken into 1 inch cubes and place chicken in large freezer bag. Pour in black pepper, ground ginger, salt, rice vinegar and mix. Place bag in refrigerator to marinate for at least 1 hour.
While chicken is marinating, whisk together water and corn starch in sauce pot until corn starch dissolves. Whisk in all other ingredients and bring to a boil on medium heat while continuously stirring. Sauce will begin to get thicker and darker in color. Reduce heat to low to simmer for 5 minutes then remove from heat to cool.
Remove chicken from refrigerator and let sit to warm up to room temperature. Place 4-5 pieces of chicken on a skewer. Heat grill to 350°F and grease with non-stick cooking spray. Place chicken on grill for 5 minutes and then flip to cook for another 5 minutes. Using a brush, lather teriyaki sauce over chicken and flip. Repeat this step another 3 more times giving chicken at least 2 coats of sauce on each side. Remove from heat and enjoy!