Mix all marinade ingredients in a gallon-sized resealable plastic bag. Add cubed pork tenderloin and knead until evenly coated. Refrigerate for 2-8 hours, turning occasionally.
Build your skewers by alternating threading pork, red pepper, and red onion pieces until the skewer is full (this recipe should make about 8 kabobs depending on the size of your skewer).
Heat your griddle to high heat and cover with a thin layer of olive oil. Place skewers on your griddle and cook for 2 minutes. Rotate 90 degrees and cook for 2 more minutes.
Continue cooking/rotating skewers until all sides have been cooked on your griddle and the internal temperature of your pork is 145 degrees (8-10 minutes total).
