Rest dough on a floured work surface for 20 minutes.
Preheat an outdoor grill for high heat and lightly oil the grate. Line a baking sheet with a layer of aluminum foil, (such as Reynolds Wrap(R)). Brush a 14-inch circle on the foil using 1 tablespoon butter.
Roll out dough to 1/4-inch thickness on the work surface. Lay onto the buttered area of the aluminum foil. Brush the top with the remaining 1 tablespoon butter. Sprinkle chocolate evenly on top. Spread marshmallows, graham crackers, and salt over the chocolate.
Slide the foil onto the grill over indirect heat. Grill, lid closed, until crust is golden and marshmallows are toasted, 8 to 10 minutes.
Cut pizza into pieces. Cool before serving, about 5 minutes.