Position racks in the upper and lower thirds of the oven; preheat to 400 degrees F. Combine the ricotta, lemon zest and a few grinds of pepper in a small bowl. Spread the ricotta mixture on the lavash, almost to the edges; transfer each piece to a baking sheet. Bake, switching the baking sheets halfway through, until the lavash is golden and crisp around the edges, about 10 minutes.
Combine the arugula, chives, artichokes and parmesan in a large bowl. Add the lemon juice and olive oil, season with salt and pepper and toss. Arrange the mortadella on the pizzas; top with the arugula salad and pistachios.