"Do you like these salads?"
Translation:¿Te gustan estas ensaladas?
In this sentence "las ensaladas" is the subject. That's why it is very important that the verb is conjugated depending on how the subject is (singular or plural).
If you want to say "Do you like these salads?" then the correct option would be "¿Te gustan estas ensaladas?" (3rd person plural). But if what you want to say is "Do you like this salad?" then the proper translation would be "¿Te gusta esta ensalada?" (3rd person singular).
Surely, the subject of the sentence "Do you like these salads?" is 'you', because it's 'you' that is doing the liking? The salads are being liked, which makes them the object.
That may be true for English, but not for Spanish. The verb "gustar" works differently, along with several others including "encantar," "interesar" and more.
You can read more about these verbs and see some good examples here: https://studyspanish.com/grammar/lessons/gustar