"Do you eat?"
When you put the subject directly behind the verb, do you always use a hyphen to separate the two, as in "manges-tu"?
Would also be fine to say "est-ce que tu manges?" but that's kind of a silly sentence. To ask, informally, if the person you are speaking to is hungry, you say "Tu as faim?" Which literally translates to "do you have hunger?"
It would also be correct to say "est-ce que tu manges ?" yes. It's not a silly sentence, it means exactly the same thing either way you say it.
The more correct is "manges-tu ?" or "est-ce que tu manges ?" - "tu manges" is mainly oral.
I should say that maybe you may not try and find a real meaning in every short sentence proposed here.
Indeed, in certain contexts, you can find "est-ce que tu manges ?".
Example: "quand est-ce que tu manges ?" Or: "Quand tu as seulement une heure de pause, est-ce que tu manges?"