Actually, this is really easy to make and works great for making ahead of time. The wetter the dough, the more holey the bread. If you are in a real pinch for time, forget about the first rise, just do the 'stretch and fold', shape it into the pan and let rise then. Top it and bake it. It wont have as much gluten development or flavor, but for the most part, will still be wonderful dipped in your spaghetti sauce. (computer with pics crashes. Photos will have to wait)
Mix the bread ingredients all together, forming a cohesive dough. Let rest for 5 minutes to hydrate.
Continue mixing, with danish whisk or wooden spoon until the dough is smoother, but still soft, supple and somewhere between sticky and tacky. Add more flour if it is way too sticky. Mist with water and mix in if it is too dry. This dough should be wetter than regular bread dough.
STRETCH AND FOLD: Spread a teaspoon of olive oil on a work surface. Rub some on your hands too. Transfer the dough to the work surface, using a bowl scraper. Now with your oiled hands, pick up one side of the dough, letting the rest of it kind of fall or stretch away. Fold it over on itself and again, pick up part of it, letting it stretch and then fold it over. Do it about 5 more times, then tuck the dough into a neat ball. At this point I put the dough into an oiled bag and pop it into the fridge until I need it, or up to 4 days. If using the same day, let it rise for about 1 hour in a bowl covered with plastic wrap and oiled.
When you are ready to bake, let the dough come to room temperature for at least an hour. Get out a baking sheet and pour some olive oil onto it. Be generous. Put the ball of dough onto the oiled pan and start to pat and pull it out to the edges wit your fingers. You can make it thicker, such as when I have used a round stoneware baking pan or thinner like when you use a bigger baking sheet. Once satisfied that it is thin enough, drizzle with olive oil, cover with plastic wrap (I take bread bags and slice up one side and across the bottom, then open it up.) Let is rest and rise about 45 minutes while preheating the oven to 500 degrees.
Once ready, drizzle the dough with more olive oil and 'dimple' it with your finger tips, poking it all over, making little craters. Sprinkle with sesame seeds, garlic salt, parmesan and, if you like, some thin sliced onions. If using onions, spray more oil over the top to keep them from drying out. Or put them on the bread after half of the baking is done. Turn the oven down to 450, pop it into the oven and bake until golden brown, about 12-15 minutes. The thicker the focaccia, the longer it will take.All the olive oil from the pan, plus the high heat, gives it a crisp crust. Serve with a marinara sauce.