Place a pizza stone in the oven and preheat to 450 degrees F.
Portion the pizza dough into six golf ball-size pieces; wrap four of the pieces in plastic and refrigerate for later use. Dust a work surface with flour and roll out the remaining two pieces of dough into your desired shape.
Top the pizzas with the Sauce, mozzarella, Parmesan and banana peppers; transfer to the pizza stone and bake for 15 minutes. Top with the reserved clams from the Sauce.
Add the warm water, yeast and sugar to a small bowl; stir to combine. Let sit until the water bubbles and smells very yeasty, 15 minutes.
Combine the flour and salt in a large mixing bowl. Make a well in the center of the flour and add the olive oil and the yeast mixture. Using a fork, gradually stir most of the flour into the yeast mixture. Turn out the dough onto a flour-dusted work surface and knead until smooth.
Lightly coat the mixing bowl with oil and return the dough to the bowl. Cover the bowl with plastic wrap and set in a warm place until the dough has doubled in size, at least 1 hour.
Steam the clams in a medium pot. Remove the clams from their shells and chop half; reserve the other half for topping the pizzas.
Sweat the onions in a pan with olive oil for about 5 minutes. Add the tomatoes, garlic, crushed red pepper, a splash of water, the chopped clams and some salt. Bring to boil, turn down the heat and simmer for 5 minutes.