
In a medium-sized bowl, whisk together mayonnaise, sour cream, red or white vinegar, Italian seasoning, olive oil, minced garlic, salt, pepper, and a pinch of granulated sugar to create the dressing.
Refrigerate the dressing for at least an hour to allow flavors to meld.
Thinly slice the cucumbers and red onion into 1/8-1/4 inch thick pieces.
In a large bowl, combine the chilled dressing with the sliced cucumbers and red onion. Toss until well coated. Serve immediately or chill longer for a refreshing experience.