Prepare the Chicken:
Using a meat mallet or the bottom of a heavy skillet, pound each chicken breast until it is uniformly about 1/2-inch thick. Cut the chicken into 2-inch cubes.
In a large bowl, mix the chicken with 3 tablespoons avocado oil and 1 teaspoon kosher salt.
Divide the chicken cubes evenly among the 8 wooden skewers.
Brush the skewers evenly with 1 cup of BBQ sauce (2 cups total, 1 cup reserved for later). Chill for at least 20 minutes.
Prepare the Salad:
While the chicken is marinating, place the corn, still in the husk, on the grill. Cook for 10–12 minutes, turning occasionally, until the kernels are tender and slightly charred. Remove the kernels from the husks and set aside.
Toss the romaine, green onions, grape tomatoes, and black beans in a large mixing bowl.
Cut the grilled corn kernels from the cob and add them to the bowl of salad ingredients.
Grill the Chicken Skewers:
Preheat the grill to medium-high heat. Lightly oil the grates to prevent sticking.
Place the skewers on the grill and cook for 15–20 minutes, turning occasionally, until the chicken is fully cooked and has a slight char.
Brush the skewers with the remaining 1 cup of BBQ sauce during the last 2–3 minutes of cooking to glaze.
During the last 8–10 minutes of grilling the chicken, add the corn to the grill if it is not yet finished.
Make the Herby Ranch Dressing:
In a blender or food processor, combine the avocado oil, large egg, coconut milk, lemon juice, red wine vinegar, kosher salt, onion powder, minced garlic, chopped dill, parsley, and black pepper.
Blend on high speed until smooth and creamy. Taste and adjust seasoning if needed.
Assemble the Salad:
Once the chicken and corn are ready, place the prepared salad mixture on large serving plates.
Top each with 1 or 2 skewers of grilled chicken and a few spoonfuls of the grilled corn.
Drizzle the herby ranch dressing over the salad just before serving.
Garnish the skewers and salad with the fresh cilantro, basil, and diced avocado.
Taste and adjust seasoning as needed. Serve immediately.