For the dough, let the yeast proof in the warm water for 10 minutes in a loosely covered bowl. Then, add the flour, sugar, olive oil and salt. Make sure to add the salt last so it doesn't inhibit the yeast. Let sit for another ten minutes, covered.
Meanwhile, chop the onion into one inch pieces and saute in olive oil with salt and pepper.
After the dough has rise, knead about 10 times. If too sticky, sprinkle flour as you knead.
Spread the dough out on your pizza pan or stone. Top evenly with sauteed onion, mozzarella, parmesan and sprinkle with as much oregano as you want.