Combine all the ingredients except for the salt in a heavy duty mixer fitted with the dough hook. Mix on medium speed until all the flour is incorporated.
Let the mixture rest for 20 minutes, then add the salt and knead on medium speed for 2 minutes. The dough should be smooth and elastic.
Cover the bowl with plastic wrap and set it on a counter for 1 hour, then place in the refrigerator for 12-24 hours. Let the dough come to room temperature about 4 hours before baking.
To make the sauce:
Put the onion, garlic and olive oil in a large skillet and place over medium heat. Cook until the onion is softened, stirring occasionally, about 10 minutes.
Add the tomatoes, 1 1½ teaspoons salt, chili and black pepper to taste. Break up the tomatoes a bit with a wooden spoon and cook uncovered over medium heat until the sauce is thickened, 20-25 minutes.
To make the pizza:
Preheat oven to 425 (220 C) degrees for at least 30 minutes.
Coat a 12-inch cast iron skillet lightly with olive oil.
Punch the dough down and form into 2 equal balls. Let the balls rest 10 minutes, then roll the them out with a rolling pin on a floured surface into circles slightly larger than than the skillet.
Transfer one piece of dough to the skillet and press it up the side of the pan. Arrange half of the salami on the dough, followed by half the cheese and the sauce. Top with the other dough round and repeat with the salami and sauce. Pinch the two pieces of dough together to seal the edge.
Put the pan in then oven and place a jelly roll pan or piece of aluminum foil on the rack under the pan to catch any drips.
Bake the pizza 20 minutes. Sprinkle the top of the pizza with the rest of the cheese and bake an additional 20-25 minutes, until the sides of the crust are golden and the cheese is bubbling.
Cool to warm or room temperature, about 30 minutes, before slicing and serving.
Notes
If you're not making your own sauce, make sure to use a thick chunky premade one (about 3 cups). If it's on the thin side, simmer in a wide skillet to reduce and thicken the sauce.
Instead of making dough, use one pound of prepared pizza dough instead.
Pizza dough adapted from Pizza Camp by Joe Beddia.