Those ingredients you listed are literally the ingredients to a dish called cucumber salad. Though usually the dressing is more of an vinegary Italian dressing instead of ranch. Just Google it.

https://www.foodandwine.com/recipes/cucumber-salad

Cut is as a prep step and it becomes a salad.

For me a salad is minimum of two uncooked ingredients.

To bolster your point I regularly make something I call cucumber onion salad with cucumber, white onion, and oil w herbs, salt and pepper. To me, it's a salad if it focuses on seasoned raw ingredients, esp vegetables, served cold. There's also the confusion over things like chicken/tuna/egg deli salads focused on being eaten as a sandwich or w crackers, and Midwest "salads" for which all rules seem to be moot except that it's likely served cold.

I mean when you put chopped iceberg lettuce and tomatoes, it's a salad... So... Two?

There is a centuries-old simple salad recipe involving just cucumbers, onions, vinegar, sugar, salt, pepper.

Anyone saying you can't have a salad out of cucumber, onions, and dressing...is wrong.

I've often had spinach, some shredded cheese, and a vinaigrette and called it salad.

Potato and Mayo = potato salad. So I would say two is the minimum. A bowl of lettuce on its own is not a salad. A salad is a classification of coke, (mainly) vegetable based dishes.

My girlfriend calls lettuce salad. A bowl of lettuce she calls a salad

I talked with a expert (my one friend who knows how to use a knife) and the conclusion is: any vegetable that is served in a different plate.