Add the sifted flour in a large bowl and mix it with the dry yeast. With your hands make a hole in the middle and add the 2 teaspoons of sugar, 1 teaspoon of salt and 6 tablespoon of oil.
Mix with a fork and slowly add the warm water, a little bit at a time.
When the ingredients are uniformly mixed, transfer the dough on a large wooden cutting board or wooden/marble table, sprinkle with flour and knead energetically the dough for at least 10 minutes, hitting it with your fists and slamming it on the working surface (you need to be rough to make the dough more elastic).
Now make a smooth ball of dough, put it in a large bowl and cover it with a thin layer of oil so it won't stick. Cover the bowl with a moist cloth and set it aside in a warm place to raise for about 1 hour and a half or until it doubles in size.
Line a baking sheet (30x40 cm) with parchment paper and with your hands stretch out the Focaccia dough in it until you have a nice rectangle with uniform thickness.
Drizzle some olive oil and set it in a warm place to raise again for about 20 minutes. Then with your fingers or with the back of a knife punch deep holes all around the dough, then cover all with enough oil to fill the holes and sprinkle with abundant salt (as much as you like).
Bake at 200°C / 390°F or 18-20 minutes or until golden brown.