is simply another version of the question particle . You can read this post for details, but the main nuance is that you only use it when it's a yes and no question. You are correct for the meaning of and . The main subtlety here is that is used to **request the ocean** , not someone.
The literal translation would be something like: "In order to request that your tears are washed away".
But the correct english equivalent would be: "Did you turn your attention to the rippling tide **in the hope** that it would wash away your tears of loneliness?".