I am trying to ask a friend whether she remembers a person I was telling her about. "Do you remember Aaron?" but I'm not sure if I should say:"Tu te souviens du Aaron?" or "Tu souviens de Aaron?"
"souvenir" is a reflexive verb. You will always use it as "se souvernir".
So it would be :
Tu te souviens d'Aaron ?
Tu te souviens de Stéphane ?
Te souviens-tu du zoo que nous avions visité ?
Est-ce que tu te souviens de l'histoire du garçon qui criait au loup ?
Please see source with the full verb
As @Stephane points out, you also misuse "de" and "du".
Note that "du" is the shortened version of "de le".
Here, you won't say "le Aaron", since it is a person, so you have to use "de".
Note that « de la » and « de l' » must not be shortened with du (as you see in my first and third examples).
For more information about "de" and "du", you may see on an other thread this answer from @Gilles
You would most commonly say
Tu te souviens d'Aaron?
if Aaron is a name (I don't know what Aaron is), but you can also say
Te souviens-tu d'Aaron?
Tu te souviens du Aaron
Do you remember the Aaron?
so it isn't correct