Mix semolina flour and yeast in a stand mixer fitted with a dough hook attachment on medium low speed. Slowly add in water. Scrape down the sides of the mixer as needed. Once combined, add about 5 cups (1200 grams) BIGA and mix until incorporated with semolina mixture.
Add granulated sugar; mix until combined.
Add extra virgin olive oil to the center of the dough and mix. Add fine sea salt.
Bump the mixer speed up to high and mix until you hear a popping sound and the dough wraps around the dough hook. The dough will be smooth but very sticky.
Prepare a metal 9 x 13 inch (23 x 33 cm) pan with a generous dusting of semolina flour.
Place the dough in the prepared metal pan and sprinkle the top and sides with a dusting of semolina flour. Cover with plastic wrap and allow to rise in a warm, draft-free place until doubled in size and the dough has filled the pan. Rise time will vary depending on the temperature of your environment.
Generously cover a clean work surface with semolina flour. Gently flip the dough onto the work surface. Using a bench scraper or sharp knife, cut the dough into rolls about 2.5 x 2.5 inches (6 x 6 cm). Be careful not to deflate the air out of the dough during this process.
Carefully transfer the rolls to parchment lined light colored baking sheets 1 - 2 inches (3 - 5 cm) apart. Ensure the tops are generously covered with semolina flour then lightly cover with plastic wrap and allow to proof in a warm (75°F - 80°F or 24°C - 27°C), draft-free place until doubled in size, about 60 minutes.
Heat oven to 400°F (205°C).
Bake for 25 - 30 minutes, rotating the baking sheets halfway through the cooking process, until lightly golden. Place ciabatta on a cooling rack and cover with a tea towel. Allow rolls to cool to room temperature before removing from the pan and slicing in half.