Do techs from a surrendering race go to the race surrendered to?

"What" I think. That is, no techs get transferred.

Yep, the answer is No.

The main way I have gotten techs from another race, besides trading, is by conquering their planets. So, the more planets a race has, the more techs you have a chance of getting. And sometimes you get ones pretty far up the tech tree.   

You get trading goods though.

The answer is no.

What ticks me off is that you don't get any of the hardware    (ships and starbases) when you conquer a civ (or they surrender to you).

Oh yeah, no techs. But like shamgar said, you have a good chance of getting a tech when you conquer a world. I don't know if espionage makes a difference, mostly because I've always had advanced espionage on all civs before I go to war with anyone.

make sure that you have constructors near any resource star bases your enemy has built prior to invading their last planet. That way you can ensure that what were their resources become yours.
If you don't kill all of their navy, they are slightly less likely to surrender, so don't crush their last fleet until you can invade their last planets in the same turn.