Unfreeze phyllo by leaving it in the fridge overnight.
Grate the zucchinis with a hand grater (not too thin) and add to a strainer. Add 1/2 teaspoon of salt and massage the zucchinis for the salt to spread evenly. Let the grated zucchinis drain for half an hour. While the zucchinis drain remove the phyllo from the fridge and let it sit at room temperature without removing it from its package.
Squeeze the zuchinnis to remove any excess water and add to a mixing bowl. Combine with the Greek yogurt, feta cheese, eggs, mint and 2 tablespoons of olive oil out of the 80 grams (keep the remaining oil for greasing the pan and phyllo). Season with a pinch of salt and a bit of pepper.
Preheat oven to 350F / 180C.
Grease well with olive oil the bottom of a 28 cm / 11 inch round pan. Place a sheet of phyllo in the pan and grease well also. Repeat until you have 5 layers. Add the filling and spread evenly with a spoon.
Overlap the excess phyllo that hangs out of the pan on top, in order to cover the filling. Make sure you grease well each phyllo with olive oil. Prick the pie a few times with a knife and bake for approximately 30-45 minutes until pie gets a nice golden brownish color.