Zanza Tech, First off skip the rice. It is absolutely useless. It will not help you fix your iPad. All it does it provides a false sense of security. It will not clean your iPad, it will not prevent corrosion.
For now you want to stop continuing to try to charge, sync or otherwise use your phone. This potentially can make a bad situation worse. Since you did not tell us how you cleaned your iPad, I would start with that step again.
Salt Water will get your components to corrode very severely. The very first step I would take is to disassemble your iPad. Use these guides to disassemble your phone. Take a careful and close look at all components and connectors. Truly assess the damage. Look for major corrosion, evaluate the pins in the connectors etc,. Take a look at all connectors as well as cable ends. After that I would suggest that you clean it a couple of times in sterile water, not drinking water (that might have helped right after it got submerged in the salt water). Use a soft brush and clean it very, very thouroughly with the sterile water. With the amount of corrosion that I envision, you will have to remove all the EMI shields. Once you got the gross contamination cleaned, use 90%+ isopropyl alcohol and clean your parts some more. For a proper cleaning, use this guide. It was written for a Apple iPhone 3G but it is still pertinent to your device as well. I can not stress the importance of a good cleaning enough, so do it over and over while replacing the alcohol after each cleaning. Do not use compressed air for the cleaning since that can drive liquid as well as corrosion particles into areas that will cause trouble later on. Do not use drinking water, if you need to use water, use sterile water. Also, you do not need to leave it to dry for a day. Isopropyl alcohol in the higher concentration will evaporate quickly and dissipate the water. The importance here is the cleaning. the best way of course would be to get it professionally cleaned Do not forget to replace the battery. This is a must and not an option. It will fail if you do not take care of it now. In your case you want to make sure that you take a close look at all components especially those around the battery and the lightning port. Once you completed all those steps, you want to measure the voltage on your battery connector to see what you get when your iPad is plugged in to the charger.Keep in mind that water damage is the hardest to troubleshoot and to repair. Hope this helps, good luck.