I have been searching for this fic for a while... Post-Chosen, Buffy moves to New England or England and finds Spike there somehow. He is a professor or teacher of English and eventually he writes a poem about death being her art, making it with her hands, etc.

I've Googled 'til I can't Google no more. Help?

Ah, thought I had it, but that's not Anaross's wonderful fic My Life Closed Twice. I do think I may have read this, but drawing a blank. If it's old, have you checked All About Spike?

It sounds very much like you may be conflating Anaross's My Life Closed Twice with another fic. This is the poem that Buffy writes in Spike's poetry class in that fic:

Death is my art. I make it every day
With my hands. I shape solid into dust
And dust into death, and it blows away.
There's no right or wrong when I slay.
I do what I do, what I must.

Death is my art. I make it every day.
Every thing in the darkness is my prey
Every shadow, I parry and thrust,
Make dust into death, and it blows away.
All color around me turns to gray
Then back to color, the color of rust.

Death is my art. I make it every day.
Day turns to night, the time to pray.
I'm alone in the dark, no one to trust.

Death is my art. I make it every day--
Make death into dust, and it blows away.

However she finds him at Oregon State in that fic and he does not have amnesia, he's just very bitter about their relationship.

I agree about the Anaross story but this also reminds me of the story All My Gold by abstracted. Sadly it is not finished.

http://dark-solace.org/elysian/viewstory.php?sid=3576