Preheat the oven to 450 degrees and place a pizza stone on the bottom rack to heat for 30 minutes. Alternatively, place an inverted baking sheet in the oven.

On a lightly floured work surface, flatten the pizza dough into two 9-inch rounds, about 1/4 inch thick; transfer to 2 well-floured pizza peels or inverted baking sheets. Let stand until slightly risen, 20 minutes.

Meanwhile, in a large saucepan, wilt the spinach with 1 tablespoon of water over high heat. Transfer to a colander and rinse with cold water. Squeeze out the liquid and chop the spinach; transfer to a bowl. Add the peas and mash lightly with a fork. Stir in the cucumber, parsley, mint, dill, and garlic. Add the yogurt, lemon juice, and 2 tablespoons of olive oil and stir to combine. Fold in the romaine and season with salt.

In a bowl, combine the za'atar with the remaining oil and a generous pinch of salt.

Shake the pizza peel a few times to loosen the dough. Dust flour under any areas that stick. Spread the za'atar oil over the dough. Slide the rounds onto the hot stone and bake for 10 minutes, until golden and crisp. Transfer the breads to a work surface and cut into wedges. Serve with the cucumber yogurt.

Za'atar is available at Middle Eastern markets and from penzeys.com.