If the idea is to minimize wiring, then you need to do up a custom wiring diagram and start crimping and soldering.
I did mine for my XS650. It's not hard. You need the ignition to feed power to the coils, but beyond that just remove the starter motor (or leave it on - you'd need a block plug to keep the oil in the engine most likely), cables, solenoid etc.
The starter motor circuit however is about the simplest circuit on the bike. Again, to 'simplify' you need to start from scratch and get rid of anything silly like safety switches on the clutch lever, side stand, auto-signal light turn-offer things, buzzers for the signals (perhaps the signals themselves as well).
My XS has a single toggle switch (no key) to turn it on/off and runs on a single 10A fuse.