Watch the Dunno Rhoads online guitar lesson by TrueFire from Play Rock Guitar 5: Lick Vocabulary
Dunno Rhoads - Lick 31 is a video guitar lesson presented by Chris Buono and is sourced from 50 Metal Guitar Licks You MUST Know.
Another must-know technique in metal licking (ew!) and riffing is the art of pinch harmonics. Few things cut through the massive mix of metal music better than these positively piercing, yet glistening tones. The great Randy Rhoads was a master at dropping pinch harmonic laced fills in-between Ozzy's vocals (and perhaps the biting of small bird's heads) with short little ditties like this lick that can be heard after Randy's solo in "I Don't Know" from Blizzard of Oz. Other pinch harmonic lick purveyors to listen for are Dimebag Darrell, George Lynch, and Zakk Wylde to name a few.