In a large bowl, combine the yeast and the warm water and set aside for 15 minutes, until yeast dissolves and foams.
In a medium bowl, mix the tepid water, 1/4 cup oil, the milk, and the salt.
In a medium bowl, combine the all-purpose and the semolina flour and add them to the yeast mixture, along with the liquid mixture. With a wooden spoon, combine the ingredients to form the beginnings of a dough. Turn out onto a lightly-floured board and knead by hand until the dough is smooth and elastic, at least 8 minutes. Place the dough in a lightly-oiled bowl, cover tightly with plastic wrap and allow to rise for 1 hour, or until doubled in bulk.
Meanwhile, make the filling. In a 12 to 14-inch saute pan, heat the remaining oil until smoking. Add the scallions, garlic and almonds and saute 2 to 3 minutes, until light golden brown. Add the chili flakes and zucchini and cook until the zucchini is very soft, about 10 to 12 minutes, stirring regularly. Cut the dough into 8 pieces and stretch each piece into an 8-inch round, which need not be perfectly round.
Place a clean pizza stone in the oven and preheat to 450 degrees F. Divide zucchini mixture among the 8 rounds of dough, distributing it evenly, and dab a little ricotta on each one. Bake until light golden brown, about 14 to16 minutes, and serve hot or at room temperature.