Preheat the oven to 150°C/300°F/Gas mark 2.
Cut the pitta breads into 2cm/3⁄4in squares, scatter over a baking sheet, then drizzle with the oil and sprinkle with the za’atar. Bake for 25–30 minutes, checking every 10 minutes or so, turning the squares and moving them around so that they all dry out evenly.
Meanwhile, put all the salad ingredients into a large salad bowl and toss together gently.
Put all the dressing ingredients into a small jug and stir together with a fork. Alternatively, put everything in a jam jar, screw on the lid and shake to mix.
Pour the dressing over the salad and toss gently together. Sprinkle over the hot croûtons and serve immediately.
For the spice blend, toast 1 tablespoon of sesame seeds in a dry frying pan until just beginning to brown, then pound with a pestle in a mortar. Mix in 1 teaspoon each of dried thyme and oregano and 1⁄2 teaspoon of salt. This mix will keep in a jam jar in the fridge for up to a month.