In the second question (without 'the'), you are asking me if I have ability in general to do this. Am I strong enough maybe? This is because without 'the', 'cups' is just in general or all of them.
In the first question (with 'the'), you are asking me to remove a specific set of cups - those on the table right now. 'The' tells me, your listener, that you think I know *which* cups you are talking about (the cups that are currently on the table I'll assume).
Of course, if you don't say 'the', and I can see a table with cups on it, I'll know what you mean in that situation. I'll just know that you've made a language error and puck up the cups. But there are situations where it won't be clear and will cause confusion.