Stretch out the pizza dough to a 12-inch circle. Place a 10-inch metal bowl upside down on a baking tray. Cover the outside of the bowl with cooking spray. Drape the dough over the bowl. (Make sure the dough is not too thin.)
Mix the melted butter and garlic powder in a small bowl and brush over the dough, reserving extra. Bake until the dough is golden brown, 20 to 25 minutes.
For the dressing: Meanwhile, mix the oil, vinegar, mustard and oregano together in a bowl.
Carefully remove the cooked pizza crust from the bowl using a kitchen towel or oven mitts. Brush the inside of the bread bowl with the remaining garlic butter and allow it cool and crisp.
For the salad: Add the lettuce, olives, peppers, strips of salami and cubed mozzarella to a bowl. Drizzle over the dressing and toss. Tip into the pizza bowl. Fold the remaining slices of salami into quarters and arrange on top of the salad. Garnish with the basil.