Back on topic - right at the beginning someone said "squirty multi-surface cleaner". Perhaps that was too subtle, so I will name the magic bug solvent I use as "Pledge".

Intended for polishing furniture, the waxy liquid acts as a mild solvent for removing dead bugs from the leading edges if you have let them dry to a crust. Spray a LOT on - we are not polishing furniture here, we're softening corpses - wait a few moments, and then wipe 'em off. It definitely works better than water.

And no, I don't recommend it for the windows.

It depends on how the wing was designed: if it was designed as a laminar flow wing, then bugs will have a measurable impact on its performance.
A conventional wing, on the other hand, does not rely on any significant portion of the profile having a laminar boundary layer, so any bugs, rivets, dents etc. won't make that much of a difference.

Are most light aircraft wings laminar flow or conventional?

Most are not laminar flow. I believe this is to do with the difficulties in manufacturing a flawless surface (no exposed rivet heads, panel edges,etc).

I drive a composite aircraft with a flawless wing that is not designed to be a proper laminar flow wing. I still clean the bugs off the leading edges if there has been a noticeable build up. This is as much about evening up stall behaviour as maintaining performance and is based on guesswork rather than empirical evidence.

I'm far more concerned about dead flies on my prop though. I've never noticed degraded performance due to flies on a wing but a prop covered in flies is less efficient and I'm sure it could be proved. My prop gets proportionately far more fly coverage than my wings. I clean my prop whenever I think its needed as a fuel saving measure.

Laminar flow wings are the exception, as far as I know. Not only for the smoothness required for the surface, but also because you need to use a laminar profile and they are not so good at high alpha/low speed (they stall earlier and more abruptly).
The P-51 Mustang springs to mind as an example of laminar wing (maybe the SF-260 too? can't remember). Nowadays I believe it's almost exclusively high-performance gliders.

and most kit/plans built canards?

presumably propellors are laminar flow?

on a seperate note Halford's do an excellent sponge for £1.99 that is for removing bugs - it has a plastic netting over it that is not abrasive. a wash with that in water that has some MER polish in it -then dried off with a clean cloth- worked wonders today.