To prepare the dressing, combine all of the ingredients in a blender or food processor and blend until smooth. Add a little water, if necessary, to reach the desired consistency. Taste and adjust seasonings as desired. Cover and place in the refrigerator until ready to serve.
Brush the corn with melted butter and place on a pre-heated gas grill over medium direct heat, or indoors on a grill pan sprayed with non-stick cooking spray set over medium-high heat.
Cook the corn until the kernels are slightly charred, rotating one-quarter turn every couple of minutes until each side is done. Remove from heat and slice kernels from cob with a sharp knife. Reserve the kernels and discard cobs. Set aside.
Add in the chopped iceberg, arugula, and fresh cilantro to a large salad bowl and toss gently to combine. Set aside.
In a large mixing bowl, combine the diced bell pepper, red onion, black beans, roasted corn kernels, lime juice, and ground cumin. Season with salt and black pepper, to taste, and toss gently to combine.
Add the seasoned black bean mixture to the bowl with the chopped lettuce and toss gently to combine. Serve immediately with Creamy Avocado Dressing or your favorite salad dressing. Enjoy!