Activate the Yeast
In a small bowl, combine the active dry yeast, 3 tablespoons of flour, and sugar. Pour in half of the lukewarm water, about 100 ml, and stir until combined. Let the mixture rest for 5-10 minutes, until foamy and bubbly.Prepare the Dough
Add the 320 g of flour, salt, and olive oil to a large mixing bowl. Pour in the activated yeast mixture and the remaining lukewarm water. Mix until a rough dough begins to form.Knead the Dough
Knead the dough by hand for 5–7 minutes, until soft and smooth. The dough may remain slightly tacky, but it should pull away from the sides of the bowl.Let It Rise
Cover the bowl with a clean kitchen towel or plastic wrap. Leave the dough in a warm place for about 30 minutes, or until doubled in size.Roll the Dough
Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper. Transfer the risen dough to the parchment paper and roll it into one large circle. Place a small bowl upside down in the center.Add the Toppings
Mix the tomato sauce with the oregano and olive oil. Spread the sauce evenly around the bowl, leaving a small border around the outside. Add the cooked ham, shredded cheese, and drained corn in even layers.Shape the Pizza Ring
Remove the bowl from the center. Cut the exposed center circle into six equal triangular sections, cutting only as far as the filling begins. Fold each triangle outward over the toppings and gently press the tip near the outer edge.Brush the folded dough lightly with water and sprinkle with seeds if desired.Bake
Transfer the pizza ring to the preheated oven and bake for 10–15 minutes, until the crust is golden and the cheese is completely melted. Allow it to rest for a few minutes before cutting or pulling apart the pieces.