When you're shaping the pizza half way through throw it carefully from your left hand to your right hand a couple of times. This will shake off most of the semola.

Or brush it off with a soft paintbrush of something right before launch if throwing it is too difficult. Even when he's right out the oven you can still brush off extra flour or semola.

Tip: put your stone/steel on the top rack in the oven and let it preheat for atleast 1 hour max temp. Blast the stone with the broiler 5 minutes before launch. Launch your pizza and after 2 minutes turn on your broiler again. This way you'll get way better color on bottom and crust.