In a small bowl, combine olive oil, Cajun seasoning, garlic salt, and red wine vinegar. Add chicken. Cover and marinate for 30 minutes.
Heat a skillet over medium heat. Add chicken and cook for 10 minutes, stirring occasionally. Add chopped red and yellow bell peppers to the skillet and cook for 5 minutes or until tender. Remove both chicken and bell pepper pieces from the skillet.
Carefully thread 1 piece of chicken, 1 red pepper piece, and one yellow pepper piece onto a small toothpick. Repeat until complete.