It's a figurative phrase ..
From the sea of something ..sea is huge and generous ..that's why we use it to figuratively describe something huge ,plenty ,generous etc ..
He means I guess in that context ,that his mom is like a sea of art ..she's skillful ,and her abilities are like a sea ,huge and generous ..so he wants her to choose a girl for him ,using her sea like skills . lol
so u can use it with anything else ..a sea of sadness ..cuz the sadness is huge and plenty ..a sea of happiness ..etc etc .