You will have an idea of the crosswind in the flare from the latest wind given to you, and the aparent drift. You should learn with a bit of experience roughly how much aileron to apply as you gently push off (not 'kick off'!) drift. There is no risk of touching a wingtip, you fly the plane rather than kick it off and hope for the best! Some types are encouraged to apply bank and sideslip. I have never applied or learnt this technique- I never needed it on the 747 and the 737 doesn't need it, though some seem to swear by it. I think it must be harder, flying a sideslip on short final. I am sure even a 757 will quite happily fly the crab technique.