You'll use the tomatoes reserved from Braised Pork with Slow-Cooked Collards, Grits, and Tomato Gravy here. Purchase one pound of pizza dough and use most of it here; the rest becomes grilled flatbreads for Red Lentil Dal with Carrot Salad and Coriander Flatbreads.
Remove dough from refrigerator. Let stand at room temperature, covered, 30 minutes.
Place a heavy baking sheet in oven. Preheat oven to 500° (keep baking sheet in oven as it preheats).
Heat a large nonstick skillet over medium heat. Add 1 teaspoon oil to pan; swirl to coat. Add onion; cook 4 minutes or until softened, stirring frequently. Remove onion from pan. Add 1 teaspoon oil to pan; swirl to coat. Add garlic; cook 1 minute, stirring frequently. Add tomatoes, 1 tablespoon oregano, pepper, and salt; cook 4 minutes or until most of liquid evaporates, stirring mixture occasionally.
Roll dough into a 13-inch circle on a lightly floured surface; pierce entire surface liberally with a fork. Carefully place dough on preheated baking sheet. Spread tomato mixture evenly over dough, leaving a 1/2-inch border. Top with onion and cheeses. Bake at 500° for 12 minutes or until crust is golden and cheese is lightly browned.
Heat a large nonstick skillet over medium-high heat. Add remaining 1 teaspoon oil to pan; swirl to coat. Add spinach; sauté 2 minutes or until spinach wilts. Top pizza with remaining 1 tablespoon oregano and spinach. Cut into 8 slices.