As everyone knows, pocket sand is already a devastatingly effective weapon. Now imagine if you were to add a full lashing to the sand as you threw it. Not only would your enemy be blinded, but they would have grains of sand stuck to their eyeballs - ouch! And however they might try to blink it out, it wouldn't go away until its stormlight ran out. Maybe you could also use both a full lashing and basic lashing to make the sand float in mid air like a deadly eyeball landmine.
Anyone else got any ideas for unconventional uses of surges?