I've looked at my hands in lucid dreams...aside from noticing an extra finger that liked to dart in and out of my hand, nothing really changed. However, I didn't look away and back, away and back, away and back, like he wants you to. You could use any object in the dream other than your hands (according to what Don Juan said) and it would be just as effective. The only reason he chose to say hands was because I suppose hands tend to stay in the dream longer than other things. Looking at a table might be hard, cause if you look away and back it might be gone.