They weren't foreshadowing anything from season 1. Benioff and Weiss just said they decided on Arya killing the NK as late as season 6 because Jon Snow was too obvious.
she did it in her fight against brieanneIncredible episode. One of my favorite battle scenes ever. Goose bumps all the way.
I’m wondering though... the move where Arya dropped the dagger into her right hand; had that particular move occured in a previous episode? I felt like I’d seen it somewhere before. Maybe a different movie, if not in GoT?
That's why all of the "What, Arya!? She came out of nowhere! Deus ex Arya!" complaints that were more vocal right after the episode dropped were so weak. It was heavily foreshadowed what was going to happen, but it still felt like a surprise. That's good directing and editing.