We've all weighted down the Ctrl key before to repair a ship haven't we... but I just found out something else!
1. Give your spaceesuit SETA, eject it from your ship and pick it up.
2. Hold down Ctrl, then hold down J, SETA will start to charge, and stay at 1000% EVEN THOUGH YOU'RE FIRING.
3. Weigh down BOTH keys before lifting your fingers off, like the old landmine trick!

Possible Problems:
You may be killed, obviously.
You will need another SETA, ah. Probably best just to do it next to somewhere where you can buy it.
You could run out of Oxygen.
New Update:
Ejecting SETA. Try not to be near anything. Collision detection will 'bounce' it far away!
Try to be 5km away from a Trading Station. With a Docking Computer. Stop your ship and eject SETA. It should be sat directly behind the ship. Now eject, pick it up, do the trick, get back in your ship, select the trading station, hit autodock and buy another SETA. Instantly.

(Neebong)