Not sure what wiring the trickle charger backwards might have done – possibly nothing. See if the battery holds a charge, and if so, try and start it. You may need a new battery though (if you've got a booster, try that). If it's the standard liquid cell battery, I find those die very easily if they're not kept charged. Just running it flat for a day (assuming it's not cold enough to freeze it) doesn't sound like enough to kill one, but maybe.
02 Polaris 600 RMK
Project sleds: 89 Indy Trail, 94 AC Pantera