What did you clean everything with? Since all your fish died in it (sorry to hear that, btw) I would rinse everything with vinegar and clean it well, soak it in hot water and rinse again. Throw out the filter cartridge you were using before and give your filter a good clean too.
If this is all done you can run it empty for a few days before adding a fish. To cycle a tank you need to add fish so ammonia and BB can turn into nitrites and nitrates (Oh god, someone please correct me if I am wrong) I know you can do a fishless cycle but it takes way longer.
You should pick up a liquid test kit (though I can't say anything because I don't have one).
It might be risky for the fish to be in there while it's cycling because the daily fluctuations of chemistry can kill.. Hmm.. Here's the sticky on proper cycling- http://www.bettafish.com/showthread.php?t=107771
Read through that.
Also, no need for aquarium salt. Remove it for the BB to do its thing. by the way, BB stands for Beneficial Bacteria.