Don't worry about making too much of this salad because the leftovers can be combined with pasta to make an outstanding pasta salad. If you cannot buy Za'atar seasoning, here is a recipe to make your own.
Whisk together everything but the oil. Then, continually whisking, add the oil in a slow stream until the dressing is emulsified. Taste. Add more sugar if necessary--the dressing should be fairly strong.
Toss all of the salad ingredients together. Add the dressing and toss again. Serve immediately.
If you have leftovers, go ahead and store them in an airtight container in the fridge. The next day boil up some pasta and toss it with the leftovers. Add some more feta cheese if you need it to be a main entree.