If you're fortunate enough to live within five blocks of a Vietnamese/other Asian grocery, like me, you can pick up a box of tempura batter mix. Or you can make it:
Tempura batter mix:
1 c. flour
3/4 c. cornstarch
3/4 tsp. baking powder
1 egg equivalent egg replacer (it will still work fine without this, just add a little arrowroot powder or a little more cornstarch)
1 c. water
(If you're feeling exotic, you can add sugar, chili powder, seasoned salt, etc.)
Silken tofu (one block makes about 3-4 "filets", and doesn't have to be silken)
Nori (or any other seaweed)
"Fish" dipping sauce:
A few tblsp white vinegar, white wine, sugar, etc - any amalgamation of the two stock ingredients and these others will work.
You'll need enough vegetable oil to keep about 3/4 of an inch in the wok or large pan at all times. It took me over an hour and a half to cook enough of this stuff for 5 people using one pan, so I advise doing both fish and veggies in separate pans at once.
Slice the veggies into round, quarter-inch-thick pieces. I like slicing the carrots in half lengthwise, and doing asparagus whole. Submerge them in the batter and throw them in the pan/wok until a little golden. (As another option, you can "paint" each piece so you don't make near as much of a mess.)
Drain and then slice the tofu lengthwise in rectangular pieces. Put the tamari in a bowl. Let the tofu soak on both sides in the tamari for a second, right before you want to fry it, then put a slice of nori on each side and submerge the tofu-nori creature in the batter. Pull it out and let the excess batter drain off for 1/8 of a second, then slide it into the oil, but try not to bring down the oil temp. too much. Let it fry on both sides until golden-ish depending on how crisp you want them.
If you're making your own batter mix, mix all the dry ingredients together evenly. Put the water in a different good-sized mixing bowl. Slowly sift the batter mix evenly over the water. Stir it literally three or four times just to get the mix to make contact with the water, but that's it; it's supposed to be lumpy.
This stuff is good served over rice or (non-greasy) lo mein.