Cut tenderloin into half-inch-thick slices. Flatten slices with the palm of your hand.
Coat a large nonstick skillet with cooking spray and place over medium-high heat until hot.
Season pork on both sides with salt and pepper.
Add pork to skillet and cook three minutes on each side or until browned.
Combine teriyaki sauce, pineapple juice, ground ginger, and cornstarch in a small bowl. Stir mixture until cornstarch is fully incorporated and there are no lumps left.
Add teriyaki mixture to pork in skillet. Bring to a boil, reduce heat and simmer for three minutes.
Remove pork from skillet, then spoon extra sauce over meat.