Char Corn: In a large pan, heat 2 tsp oil over medium-high heat. When the pan is hot, add corn kernels. Season with salt. Cook for 4-6 min, swirling the pan occasionally, until corn is deep golden-brown. Transfer to a bowl and set aside.
Dress Cabbage: In a medium bowl, whisk together lime juice, 1 tsp maple syrup and 2 tsp oil. Season with salt and pepper. Add cabbage and half the cilantro, then toss to combine.
Make Dressing (Optional): To a blender or small food processor, add avocado, yogurt, vinegar, maple syrup, garlic powder, onion powder, dill, dijon and chives. Season with salt and pepper. Blend until smooth. Season with salt and pepper to taste. Set aside. Note: If you're not adding avocado dressing, consider adding the lettuce to the bowl with cabbage so it gets a little something on it. See note if making recipe ahead.
Crisp Tempeh: In the same pan used for corn, heat 1 tbsp oil over medium-high heat. When the pan is hot, add tempeh. Cook for 5-7 min, flipping tempeh occasionally, until golden and crisp on all sides.
Glaze Tempeh: Reduce heat to medium-low. To the pan with tempeh, add BBQ sauce and tamari. Cook for 1-2 min, stirring often, until BBQ sauce reduces slightly and nicely glazes the tempeh. (Depending on the consistency of your BBQ sauce, you may need to add 1-2 tbsp water to thin out.)
Assemble Bowls: Divide rice or quinoa between bowls. Arrange slaw, lettuce, tomatoes and charred corn on top. Top with BBQ tempeh. Drizzle with avocado dressing, if using. Sprinkle with remaining cilantro. Drizzle more BBQ sauce on top, if desired.