Prepare the chicken by pounding it to an even thickness, cubing it, and mixing it with avocado oil, kosher salt, and BBQ sauce. Marinate for at least 20 minutes.
Make the herby ranch dressing by emulsifying light-tasting oil with egg (if using), then add coconut milk, lemon juice, red wine vinegar, kosher salt, onion powder, and garlic. Blend until smooth and mix in dill, parsley, and pepper.
Grill the corn for 8-10 minutes after drizzling with avocado oil. Set aside.
Soak wooden skewers for 30 minutes, then thread marinated chicken on them. Grill for 10-15 minutes, basting with BBQ sauce.
Combine romaine, green onions, tomatoes, cilantro, basil, corn, and black beans (if using) in a bowl. Add grilled chicken skewers and drizzle with ranch dressing before serving.