Figured I would answer a couple of questions while fixing some bugs and glitches on the site. 
They should be able to get the necessary salt from a healthy diet that includes a variety of greens. If you have a pellet free diet, then a salt lick might be an option for salt intake. There was a really great thread with detailed information — alot of back and forth that then provided some great information and thoughts. https://binkybunny.com/FORUM/tabid/54/aft/117857/Default.aspx (be sure not to reply to that older thread though– just come back to this current one to comment)
Note: Salt blocks may increase water consumption so make sure to have plenty of fresh water.
Your bunny may be chewing it more as a “toy” type of thing, as chewing on stuff is part of their nature, and maybe she ended up liking the taste. There could also be a medical issue that is making her crave an excess of salt, but only a vet can determine that.