Preheat the grill to 300°F (low to medium setting).
In a medium bowl, add chicken, garlic, thyme, olive oil, salt, and pepper. Toss until well coated. Cover and refrigerate for 20 to 30 minutes.
Thread chicken onto skewers. Place kabobs and corn on the grill and cook for 10 minutes. Turn and cook another 10 minutes, or until corn is starting to show char marks.
In a medium bowl, add the tomatoes, scallions, olive oil, vinegar, salt, and pepper. Toss until well coated. Serve with chicken and corn.