スープをこぼしてしまったって英語でなんて言うの？

Both phrases indicate that there is now soup on the table and that you would like it cleaned up.

You need to be polite when asking to clean up the mess made by the soup, so use, "Could you."

All phrases are clear that I have spilled soup on the table and need help to clean it up.
Example:
Me: Excuse me waiter.
Waiter: Can I help you?
Me: Yes, can you help me clean the table?
Waiter: Yes sure, what happened?
Me: I spilled some soup.
Waiter: No problem I will clean it quickly.

1. here you declare that you have somehow created an untidy area on your table or nearby. In context, it should be clear what has happened. The waiter should then help you to clean or clear up themselves. It is not an unusual situation and really it's their job to tidy up in such a situation.
   "Excuse me, but sorry, I made a mess."
   "It's alright sir, we'll take care of it."
2. Here you offer to clear up yourself. In any professional restaurant, the staff will clear up in this situation...but they will appreciate that you offered to do it yourself!

Accidents will happen(adage) and of course "to err is human" (shakespeare)
Now and again we all have that moment when it goes all wrong in a restuarant!
And we make a mess and spill something ;-(
Don;t worry the staff are probably used to the odd accident through out the day.
"it comes with the territory": Don't panic! Just let the staff know the situation:
"There has been a small accident with the soup" and they will no doubt come to the rescue!

These are both okay when telling the waiter you spilled your soup. You are also asking for something to clean up the spilled soup with.

These sentences indicate that someone has spilled their soup.