Prep by cubing/dicing up all the pasta salad ingredients (including the lettuce) into somewhat equal sized pieces while you cook the rotini in salted boiling water according to the package's instructions.
In the bottom of a large salad bowl, make the dressing by combining the mayo, red wine vinegar, pepper, salt, oregano and red pepper flakes - whisk until smooth.
Build the pasta salad. Start with the iceberg lettuce and then fill in the rest of the ingredients. (Be sure to rinse the cooked pasta in ice cold water before adding it to the bowl!)
Mix and serve right away at room temp or you can put it in the fridge and serve chilled later.