haha....grainy tater tots! i love it.
when you are freezing it,if youve already opened it, i would wrap it in plastic wrap and put it in a ziplock.
yeah, i would thaw it first before using it. it will take on flavor better this way.
though i usually steam mine before frying/baking, whatever so it that case, it doesnt have to be totally thawed.
if you want to speed thaw it, you can submerge the unopened package or the ziplock baggie into water and pop it in the microwave for 2mins or so...just dont over do it so you dont actually cook it.
and though i havent personally tried it, people have marinated tofu in the freezer...by taking the marinade and tofu, throwing it into a ziplock and freezing it. it should suck up the flavors well. i would think this would work well for tempeh too.