Position racks in the middle and upper third of the oven and preheat to 350 degrees F. Line a 9-inch pie plate with the dough, crimping the edge with your fingers. Poke the bottom of the crust all over with a fork. Line with foil and fill with pie weights or dried beans. Bake on the middle rack until golden around the edge, about 20 minutes. Remove the foil and weights; continue baking until golden all over, about 10 more minutes.
Meanwhile, core the tomatoes and cut into 1/2-inch wedges; toss with 1 1/2 teaspoons salt. Spread the tomatoes in a single layer on paper towels to drain until ready to use.
Melt 1 tablespoon butter in a medium saucepan over medium heat. Add the corn and cook, stirring occasionally, until tender, about 5 minutes. Transfer 1/2 cup of the corn to a large bowl.
Add the heavy cream to the saucepan with the remaining corn and bring to a simmer. Carefully transfer the mixture to a blender and puree until smooth; transfer to the bowl with the corn. Whisk in the eggs, half each of the scallions and cheese, and a few grinds of black pepper; pour into the crust. Bake on the middle rack until the custard is just set, 35 to 40 minutes. Remove from the oven and increase the temperature to 400 degrees F.
Mix the remaining scallions and cheese, the panko, thyme, paprika, cayenne and 1/4 teaspoon each salt and black pepper in a bowl. Sprinkle 1/4 cup of the mixture on top of the pie. Pat the tomato wedges with paper towels to absorb the excess moisture, then coat with the remaining panko mixture and arrange on top of the tart. Sprinkle any remaining panko on top; dot with the remaining 1 tablespoon butter. Return to the oven on the upper rack and bake until the top is golden, about 15 minutes. Let cool 30 minutes before slicing.