Directions:

Heat a grill to medium-high heat.   Place the sliced zucchini, yellow squash and tomatoes in a colander set over the sink or a large bowl.  Toss with ¾ teaspoon kosher salt.  Let sit 20-30 minutes to drain excess liquid (this prevents pizza from being soggy after topping).

Meanwhile, transfer the pizza dough to a lightly floured work surface.  Divide the dough into four equal portions.  Let rest 10 minutes.  Meanwhile, shape each piece of dough into a flattened round, about 6-7 inches in diameter.  

When the coals are heated, generously oil the grates (you can use tongs holding a wad of paper towels dipped in olive oil).  Carefully place the shaped dough rounds onto the grill and cover.  Let cook until nicely browned on the bottom surface, and large bubbles appear on the top surface, about 3-4 minutes.  Carefully remove the partly cooked dough rounds from the grill for topping.

Transfer the dough rounds to a work surface so that the cooked side is facing up (this is the side that will hold your toppings).  Top evenly with sliced zucchini, yellow squash, tomatoes, and red onion.  Sprinkle with minced basil, freshly grated Parmesan and crumbled feta.  Season with pepper, to taste.  Carefully return the topped pizzas to the grill; cover and let cook until the bottom surface is nicely browned and the cheeses are melted, about 4-6 minutes.  Remove from the grill.  Serve warm.

For Basic Pizza Dough:
Measure the warm water into a 2-cup liquid measuring cup. Sprinkle in the yeast and let stand until yeast dissolves and swells, about 5 minutes. Add the room temperature water and oil and stir to combine.

Place the flour and salt in the bowl of a stand mixer fitted with the paddle attachment. Briefly combine the dry ingredients at low speed. Slowly add the liquid ingredients and continue to mix at low speed until a cohesive mass forms. Stop the mixer and replace the paddle with the dough hook. Knead until the dough is smooth and elastic, about 5 minutes. Form the dough into a ball, put in a deep oiled bowl, and cover with plastic wrap. Let rise until doubled in size, about 1-1/2 to 2 hours. Press the dough to deflate it.

To bake, place a pizza stone in the lower third of the oven. Heat oven to 500 degrees F for at least 30 minutes. Turn the dough out onto a lightly floured work surface. Divide the dough into two equal pieces. Form both pieces of dough into smooth, round balls and cover with a damp cloth. Let the dough relax for at least 10 minutes but no more than 30 minutes.

Working with one piece of dough and keeping the other covered, shape the dough and transfer to a pizza peel or round of parchment dusted with semolina or cornmeal. Top as desired. Slide the dough onto a pizza stone. Bake until the crust edges brown and cheese is golden brown in spots, about 8-12 minutes. Repeat with remaining ball of dough or freeze for later use.