Preheat oven to 424 degrees F.
Dust a clean work surface lightly with flour. Place entire dough on surface, spread it out, and flatten with fingers or rolling pin until you form a large rectangle (about 12 inches by 15 inches, and 1/4 inch to 3/8 inch thick). Dust sheet pan with flour and place dough on pan, stretching it to reach all sides. Using a kitchen spoon, smooth a thin layer of tomato sauce over pizza dough all the way to the edges. Sprinkle with olives. Place mozzarella and crumbled tuna over entire rectangle. Sprinkle with hot pepper and bake 20 minutes, or until golden brown on bottom and cheese is melted. Remove and serve immediately.
Saute the onion and garlic in the olive oil over medium heat until translucent, but not brown (about 10 minutes). Add the thyme and carrot and cook 5 minutes more. Add the tomatoes. Bring to a boil, lower the heat to just bubbling, stirring occasionally for 30 minutes. Season with salt to taste. Serve immediately, or set aside for further use. The sauce may be refrigerated for up to one week or frozen for up to 6 months.