Preheat oven to 250F.
Arrange tomato slices on a baking sheet and drizzle with EVOO, oregano, salt and pepper. Roast in oven until beginning to caramelize, 1 hour, then turn oven up to 325F for another 30 minutes. Remove tomatoes from oven and allow to cool slightly.
If using fresh pizza dough, turn oven up to 450F. Roll dough out to about 12-inches in diameter across on a lightly floured surface. Transfer dough to a cookie sheet and bake in oven until golden brown, 10-12 minutes. Let cool.
While the crust is cooling, add the arugula, walnuts, nutmeg and a splash of water to the bowl of a food processor. Add some salt and pepper, and pulse to roughly chop. With machine running, stream about 1/3 cup EVOO (eyeball it) into processor to make a pesto. Transfer pesto to bowl and stir in 1/2 cup Parmigiano (eyeball it).
Spread pesto on baked pizza crust and top with shredded provolone and remaining Parmigiano. Arrange slow-roasted tomato slices on pizza and return to oven to melt cheese, about 10 minutes. Let pizza sit a couple of minutes before slicing and serving.