Do you think it's alright if I tell this guy to fuck off?
Why do you want to say that to him?
I cannot stand him constantly talking to me while I'm eating.
I understand why you're annoyed, but it's rude to use foul language towards another person like that. I think you should politely let him know that you want to be left alone while eating.
But he's an asshole.
He might be annoying, but cursing at him isn't the way to get him to leave you alone. Just tell him that you aren't interested in having a conversation with him.