Hi @MatthewCrochet,
I'm guessing that you are a student, and am basing my answer on that guess...
Unfortunately, you won't be able to delete anything yourself. Your teacher or someone on your school/institution Canvas team *may* be able to delete a file uploaded as part of a submission (depending on what permission settings your school/institution chose), but won't be able to delete the entire submission attempt. I say it this way because there are times where assignments have a limited number of submissions, and once you submit something you use one of those available attempts. If you no longer have any submission attempts left, your teacher would have to increase the number of attempts available for the assignment for the whole class.
I would suggest that you contact your teacher and let them know you need to have the file deleted or just need a resubmission attempt made available. They should be able to handle things from there, but of course I can't guarantee that they will say yes ot your request.
I hope this helps.
-Chris
