Take a medium sized pot, and warm up kosher salt and cups of water until dissolved. Do not bring to a boil. Clean and cut the chicken breasts into 1-inch cubes. Add the chicken into the brine mixture and brine for 15 minutes only. Drain and pat the chicken completely dry with paper towels.
While the chicken brines, slice the zucchini into ½-inch rounds and cut the bell peppers and red onion into 2-inch pieces.
In a large bowl, whisk together the olive oil, soy sauce, honey, onion powder, garlic powder, Italian seasoning, Liquid Smoke, and smashed garlic cloves.
Add the dried chicken to the marinade and toss until well coated. Cover and refrigerate for at least 1 hour or up to 8 hours.
About 30 minutes before grilling, soak the bamboo skewers in water. Preheat the grill to 400°F (204°C).
Thread the marinated chicken, zucchini, bell peppers, and red onion onto the skewers, alternating as you go. Leave a little space between each piece so everything cooks evenly.
Place the skewers on the hot grill and cook for 10 to 12 minutes, turning every 2 to 3 minutes for an even char. Grill until the chicken reaches an internal temperature of 165°F (74°C).
During the last few minutes of grilling, brush the kabobs with your favorite barbecue sauce, if desired. Remove from the grill, rest for 5 minutes, garnish with fresh parsley, and serve warm.