In a small bowl, combine olive oil, lemon juice, lemon zest, garlic, 1 teaspoon salt and ½ teaspoon pepper.
In a gallon size Ziploc bag or large bowl, combine chicken and olive oil mixture; marinate for at least 2 hours, turning the bag occasionally. Drain the chicken from the marinade.
Preheat grill to medium high heat.
Add chicken to grill, and cook, turning occasionally, until chicken is completely cooked through, reaching an internal temperature of 165 degrees F, about 4-5 minutes per side. Let cool before dicing into bite-size pieces.
