Once zucchini has been grated (I recommend a food processor) lightly salt the zucchini and transfer it to a colander. Let stand 30 minutes and press all remaining liquid out of zucchini.
In a medium-sized mixing bowl, combine zucchini, flour, parmesan cheese, mozzarella cheese, eggs, pepper and salt. Mix well.
Spread the mixture on a greased and floured baking tray. Bake for 25 minutes in the preheated oven.
Remove the pizza base from the oven and heat the grill. Brush the top of the base with oil and then grill for 3 to 5 minutes until the top is lightly browned.
Allow the base to cool slightly and slide spatula underneath all edges and under the middle. Place a large baking tray over the top of the base and gently flip the base over so that the bottom of the base is now facing upwards. It may be necessary to cut the base in half to facilitate the flipping. It is also okay to omit the flipping stage, but the base won't be as crunchy.
Brush the top of the base with oil and grill for another 3 to 5 minutes until the top is browned. Cover with toppings as desired.
For a Crispier Pizza...
This will be a non-traditional pizza base as it will be somewhat soft. Depending on your toppings, you may need to bake it at 200 degrees C for a few more minutes to heat toppings and further reduce sogginess.