Demystifying the Fourier Magic
xrds.acm.org
xrds.acm.org
If the aim is to 'abstract' it, then call it 'abstraction' but demystifying is rather far-fetched.
Yes, the Fourier transform is no more than the expression of the elements of a Hilbert space in a complete basis: get over it and move on? Is it clear? You can generalize it even more.
But honestly, as Abhyankar has been quoted saying, the real question is... "What is a polynomial?" That is the really difficult question to answer.
Sorry for the rant but titles should really be at least honest (I agree they have to be attractive but...).