Start by seasoning the zucchini. Toss the thinly sliced zucchini with 1/2 teaspoon salt in a colander and let it sit for 30 minutes. This process draws out excess moisture. Afterward, rinse the zucchini under cool water and pat dry with paper towels.
In a cast iron skillet, heat one tablespoon of olive oil over medium heat. Add the sliced bell pepper, onions, and mushrooms. Sauté for 3 to 5 minutes until they soften slightly and release any remaining moisture. Set aside.
Prepare your grill for preheating. While the grill heats, spread a thin, even layer of pizza sauce over the prepared pizza crust. Season the sauce lightly with salt, pepper, and scatter fresh basil across the surface.
Arrange the sautéed vegetables, black olives, and cherry tomatoes evenly over the pizza. Finish by sprinkling the grated mozzarella and crumbled feta generously over the toppings.
Preheat the oven broiler to high heat.
Lightly brush the grill grates with olive oil. Carefully place the pizza crust directly onto the grill grates or on a pizza pan, depending on your preference. Keep the grill lid open and monitor the pizza closely; it should cook within approximately 5 minutes, depending on the grill’s intensity. The bottom of the crust should become crisp and develop a rich brown color.
Once the crust is beautifully grilled, transfer the pizza to an oven-safe pan and place it under the broiler until the cheese melts, bubbles, and turns golden brown. Watch closely to avoid burning. This final step gives the pizza a perfectly caramelized top and an irresistible flavor.