Oooooh man! Sorry to hear that. It can be saved if you act fast...but I'm sure you've got more important things to deal with at the moment...
I've had lots to deal with over the last five days. However, since I'm approaching sanity, what do I need to pay attention to in particular?
How deep did she go? If just to engine level...
First, check the oil...if there's no water in the oil some of this can be skipped...but for sure, pull the plugs/lube...if there's no saltwater in the oil or cylinders you've got it easy. Rusty plugs? May have had saltwater in the cylinder via the pipes/open exhaust valve...
If there's saltwater in the oil or cylinders, you may also have a stuck valve. The safest thing to do is pull the heads and clean make sure the valves are clear...
I've gotten away with the following before...when acting fast...and things hadn't rusted up (particularly the valves).
Rinse the bike off with clean water, shooting it even in the pipes. Pull the alternator cover and don't be afraid to spray water in the vents, flushing it as well. Let dry in the sun whilst you do the other stuff (dry before running).
Drain the oil. Pull the plugs. Squirt oil/wd40 or something in the plug holes.
Drain the carbs...just in case. They have a handy screw on the bottom of each. Get fresh fuel flowing through them (you should have to pull a vacuum on the petcock to do so...)
If there was saltwater in the oil, Put several quarts (like 6) of diesel fuel in the crankcase.
Turn over several via starter several times. If the starter will turn her, she can be saved, otherwise it's time for insurance or an engine out rebuild.
If she turns over, do this several times. Drain out the diesel. Fresh oil and filter. Start her up and run her till hot. Let her cool. Run her again till hot. Drain oil (while hot or at least warm). Fresh oil and filter again.
Change the wheel bearings. All 4 of 'em. Whilst you have the rear off, pull the pumpkin. Drain it. Rinse it well with diesel. Clean inside the swing arm with water to rinse the salt out. Re-install/lube everything as normal...swing arm bearins may be okay...while you have the wheels off and bearings out, rinse the nooks and hollow crannies well.
Go ride. Change the oil and rear end grease after 500 miles.
If she went deeper...like over the Ignition module...pull all the submerged electrical parts and clean the connectors with water, then wd 40, then lube with dialectric grease.
Pay attention to the u-joint and swing arm bearings in the future...the seals may have been penetrated by salt water and that will accelerate wear.