Preheat your grill or grill pan over medium-high heat.
Brush the zucchini planks and corn with olive oil and sprinkle lightly with salt and pepper.
Grill the vegetables for about 3–4 minutes per side until grill marks appear and vegetables are tender. Turn the corn occasionally to get an even char.
Remove from grill and let cool slightly. Cut the corn kernels off the cob and slice the zucchini into bite-sized pieces.
Prepare the tahini dressing by whisking together tahini, lemon juice, olive oil, maple syrup, grated garlic, and salt. Slowly whisk in water, one tablespoon at a time, until smooth and pourable.
In a large bowl, combine grilled corn, zucchini, and fresh herbs. Drizzle the tahini dressing over the top and toss gently to coat.
Sprinkle with crumbled feta cheese if using, and serve either warm or at room temperature.