In a large bowl, mix together flour, yeast, salt, and sugar. Add 1 cup of warm water, then mix to combine.
Slowly add the olive oil. Fold the dough into itself, punch down, fold into itself again and knead. Continue this process of folding and kneading, while adding flour to the bottom of the dough ball to prevent sticking, about 10 minutes. The dough should be very moist and sticky.
Cover the bowl with plastic wrap and allow the dough rise in a draft-free place at room-temperature until doubled in size, about 1 hour. Remove the plastic, sprinkle with flour, punch down and fold into itself a few more times. Cover and allow to rest again, about 15 minutes.
Generously grease 2 - 10” x 10” baking pans. Divide the dough into two pieces and press each piece into a pan, stretching the dough to fit into all the corners evenly.
Cover the dough with the olives, oregano and sea salt. Drizzle with olive oil. Heat oven to 450˚F. Bake the focaccia for 30 minutes or until the top and bottom crust turn golden brown. Transfer to a cooling rack. Once cooled, cut into pieces and serve at room temperature.