Adjust oven racks so it is divided into thirds and preheat the oven to 450 degrees F.
Evenly divide the dough into 6 pieces. Sprinkle work surface with flour and knead dough lightly. Lightly flour a rolling pin and roll each dough into a 6 inch circle. Place the circles onto 2 large nonstick cookie sheets. Sprinkle with cheese and bake until the cheese is melted and crusts are golden, about 10 minutes (switch pans between racks halfway through baking time.) Remove crust to a cooling rack and cool 2-3 minutes.
In the meantime, whisk the vinegar, oil, honey, garlic, mustard, coriander, salt, and pepper in a large bowl. Add in the greens and apple and toss to coat. Spoon the salad over the crusts and top with walnuts. Serve immediately