Preheat the grill to medium-high heat.
Place the husked corn directly on the grill. Grill for about 10-12 minutes, turning occasionally, until the corn is charred and cooked through. Remove from the grill and let cool.
While the corn is cooling, toss the diced zucchini and red bell pepper in 1 tablespoon of olive oil, salt, and pepper. Grill the vegetables for about 5-7 minutes until they are tender and have grill marks. Remove from the grill and let cool.
Once the corn is cool enough to handle, cut the kernels off the cob and place them in a large mixing bowl.
Add the grilled zucchini, red bell pepper, red onion, cilantro, and feta cheese to the bowl with the corn.
In a small bowl, whisk together the remaining olive oil, lime juice, garlic powder, salt, and pepper. Pour the dressing over the salad and toss gently to combine.
Serve immediately or refrigerate for 30 minutes to allow the flavors to meld.