Preheat the oven to 375 degrees. Using 2 baking sheets, place 2 tortillas side by side on each sheet. With a pastry brush, lightly brush each tortilla with some of the olive oil. Flip the tortillas and brush again. Bake 8 to 10 minutes, flipping over the tortillas and alternating the placement of the baking sheets halfway through the cooking time. Also, during the first few minutes, use a knife point to pop any air bubbles that might develop. The tortillas should be golden and crisp when done. (The tortillas may be prepared to this point up to 3 days in advance. Cool completely, seal in a plastic bag, and refrigerate until ready to use.)

In a large bowl, combine the tomatoes, olives, zucchini, onion slivers, oregano, pepper, and olive oil and toss well. Gently fold in the feta cheese. Scatter all over the 4 tortillas. Bake 12 minutes, or until the feta is sizzling and the zucchini softened. Alternate the placement of the baking sheets halfway during the cooking time. Cut and serve immediately