> Python somehow magically slices unicode strings without chopping characters in half.

Well, that rather depends on what you mean by "character" and "in half".

    >>> s = u're\u0301sume\u0301'
    >>> print s
    résumé
    >>> len(s)
    8
    >>> for i in xrange(len(s)):
    ...     print s[i]
    ... 
    r
    e
    
    s
    u
    m
    e

    >>> print ' '.join(s)
    r e ́ s u m e ́