Heat the oven to 400 degrees and line a baking sheet with parchment paper.
Roll the pizza dough into a rectangle about 12 by 16 inches on a lightly floured surface.
Layer the sliced ham evenly over the dough, then sprinkle the shredded mozzarella on top.
Roll the dough tightly from the long side into a log and pinch the seam to seal.
Place the roll seam side down on the baking sheet. Brush the top with melted butter and sprinkle with garlic powder.
Bake for 20 to 25 minutes until the crust is golden brown. Let it rest for 5 minutes, then slice into 8 pieces.
While the stromboli bakes, combine the chopped romaine, halved cherry tomatoes, and sliced cucumber in a large bowl. Toss with ranch dressing just before serving.