Whisk together olive oil, red wine vinegar, garlic powder, dried Italian herbs, salt, and sugar in a bowl. Set this aside as it intensifies in flavor while you assemble the rest of the salad.
In a large, shallow salad bowl, add the radicchio, red, yellow, and orange peppers, chickpeas, peperoncini, salami, black and green olives, cauliflower, cherry tomatoes, parsley, red onion, cucumber, and mozzarella.
Drizzle the prepared dressing over the salad. Toss gently yet thoroughly, ensuring that every piece is coated with the dressing for full flavor integration.
Serve immediately for the freshest flavor, or cover and refrigerate if you're serving later. Reserve some dressing to add just before serving if the salad sits for a while.