Preheat the grill to high. Half the zucchinis, length-wise. Cut the peppers into large pieces and remove seeds. Separate the layers of the pitas to make 6 pita circles.
Drizzle olive oil over the zucchini, peppers, and pitas. Then salt and pepper to taste. Roll them around, to make sure they have a good coating of oil. Grill the veggies for about 2-3 minutes per side, until nice grill marks have formed and the veggies are slightly tender. Then grill the pitas, for 30-60 seconds per side, until toasty.
In a large serving bowl, add all the other veggies, olives, and herbs. Once the grilled vegetables have cooled, chop them into 3/4-inch cubes and add them to the serving bowl.
Break the pitas into bite-size pieces and add to the mix. Toss the salad and sprinkle the feta over the top.
Mix 1/4 cup of olive oil and the juice of one lemon in a small bowl. Season with cumin, then salt and pepper to taste. Whisk well. Drizzle over the salad and serve.