"Ellos quieren comer una ensalada."
Translation:They want to eat a salad.
Sounds like they want to eat one salad?? Would it be more accurate to say ensaladas or las ensaladas, if the article is necessary?
They want to eat one salad apiece. Spanish is distributive; if you say, "Ellos quieren comer ensaladas," you're stating that they each want to consume more than one salad.
Yes, they only want to eat one salad! - If they want to eat more salads, then DL would write "Quieren comer varias ensaladas".