In a large bowl, combine the water, oil, flour, semolina, salt and yeast. Stir with a wooden spoon until a soft, slightly sticky dough is formed. Cover loosely with plastic wrap and a damp kitchen towel. Let rise for 30 minutes in a warm spot.
Place the dough in a well-oiled 9x13-inch baking pan and let rest for 10 to 15 minutes, then pat and stretch it to cover the bottom of the pan. Let the dough rest, covered, for another 30 minutes.
Preheat oven to 425°F.
Meanwhile, to make the sauce, place the tomatoes (with their juice), garlic, oil, and seasonings in a food processor or blender. Blend until smooth.
Top the the dough with the sauce, spreading it into an even layer. Then sprinkle on the cheeses, top with pepperoni and season with a bit of oregano. Bake until golden brown and bubbly, about 25 minutes. Remove from the oven and let cool for about 5 minutes before slicing and serving. Enjoy!