In a mixing bowl, whisk together honey, barbecue sauce, apple cider vinegar, garlic powder, onion powder, salt, and black pepper. Add the chicken breasts to the bowl, ensuring they are coated evenly. Cover and refrigerate for at least 30 minutes, or up to 2 hours for more flavor.
Preheat your grill or grill pan over medium-high heat.
Remove the chicken from the marinade and place it on the hot grill. Cook for 5-7 minutes per side, or until the internal temperature reaches 165°F. Brush occasionally with the remaining marinade for extra flavor.
While the chicken is cooking, in a large mixing bowl, combine sliced cucumbers, cherry tomatoes, red onion, and parsley.
In a small bowl, whisk together olive oil, red wine vinegar, and a pinch of salt and pepper. Drizzle over the salad and toss to combine.
Once the chicken is cooked, remove it from the grill and let it rest for a few minutes. Slice and serve alongside the garden cucumber salad on a serving platter.