Put romaine, arugula, red onion, salami, cheese, tomato and basil in large bowl. Add black olives, artichoke hearts, pepperoncini and capers, if using. Cover with lightly dampened paper towel; keep refrigerated until ready to use, up to 4 hours.
Combine olive oil, both vinegars, garlic, salt and pepper in small dish. Can be kept at room temperature 3 hours.
To serve, pour dressing over salad. Toss several times.