Do this by unplugging the sensor harness, warming up the engine, and creating a lean condition at about 2000 rpm for 1 or 2 minutes. Create a big enough vacuum leak so that the engine begins to slow down.
Unfortunately, most Hondas use a speed/density system rather than mass airflow to meter fuel. That means that a vacuum leak will simply boost the idle speed rather than turn the mixture lean.
Two off the wall ideas to make this car unique that may be more trouble than they're worth:
1) Turbocharge it. John Wayland rode in Willie Williford's Honda Insight that has a turbocharger installed in it running 5 psi of boost. 0-60 mph was about 7 seconds and there was no penalty in fuel economy if driving style was kept unchanged. You could go baiting Porsche Boxters, Audi TTs, and BMW Z3s.
2) Convert it to electric. The glider is perfect for making an 80+ mile range conversion using lead acid batteries due to its low weight and good aero.
You would have a hard time using such an additive with an Insight. The main battery pack consists of 120 sealed "C" size (IIRC) NiMH cells. Even if it were compatible with the chemistry, you would need to break down the battery pack and somehow evenly inject the additive into each battery cell.
I guess you could use it in the much smaller 12V lead-acid starter battery, but they likely cost less than $50 to replace, so what's the point?