With my short friends (I'm a 5'8" woman), I am a bit silly... I'll bend over so we're more even to hug them, and just stand up straight still holding them. They're usually a bit startled... but the 15 yr old in me is amused.
Most of my solutions aren't, really... just bending a bit, or finding times other than when you're standing, i.e. you're sitting and they're not, etc. Otherwise, I think you're just screwed. As for a hugging "technique"... the only bad thing I've ever noticed about hugging the rare person who is that much bigger than me, is that they sometimes sort of squish me into their side and it's a bit like hugging a rock. Try to make yourself more pliable, soft... hugs should be comfortable!