An easy, flavorful way to combine two summer classics: grilling and heirloom tomatoes. Choose heirlooms in contrasting sizes, shapes, and colors for the most visual appeal. For the crispest pizza, make sure you roll your dough out thinly and evenly and don't overload the top with tomatoes.
Divide the pizza dough into 4 equal balls. Dust a work surface with flour and roll each ball out to a rough circle about 9 inches in diameter. Brush each side of the circles with olive oil and place on baking sheets.
Preheat a grill on medium heat.
Working with 1 piece of dough at a time, place it on the grill rack and cook, rotating the crust frequently with tongs to help it cook evenly, until darkly browned on the bottom and air bubbles form on top, 3-4 minutes.
Transfer browned-side up to the baking sheet and spread 2 tablespoons of the pesto on the browned side. Top with a few slices of tomato (don't cover the entire surface or the pizza will end up soggy), season the top with 1/8 teaspoon each of the salt and pepper, and dot with goat cheese.
Slide or lift the pizza back onto the grill, close the grill cover, and cook, rotating the pizza every now and then, until the bottom is deeply browned and the cheese begins to melt, about 3 minutes. Slide or lift the pizza back onto the baking sheet. Repeat with the remaining dough.