[minimal]

Why are salts not considered Lewis acids?

Why is NaCl not similar to HCl in that respect. 
Both are very polar.  NaCl is normally considered to be ionic as opposed to covalent, whereas HCl is not afaik.  I don't see how that would affect the outcome though, since that would just mean that Sodium becomes a cation, and as far as I can tell, that would make it an electron acceptor and a lewis acid. 
I understand that salts can be either mildly acidic or basic.  I am assuming the answer is that it is mildly acidic? If so, why only mildly so?
Another good example that I'd like addressed is that of Ammonium Chloride.  Now, it is a salt, however, wouldn't it be an acid too.
Err wait, I was just looking at it.  Would the answer be that if it was an acid, and it donated a proton it would no longer be the ammonium +1 cation and balanced by the chloride -1 anion.  Thus it would be -1 total charge.  But wait every acid would change charge upon disassociating, so that can't be it.  Overthinking....please help.

Thanks

[azmanam]

'salts' can be considered lewis acid/lewis base complexes, if you'd like, but a 'salt' is not the lewis acid.

try these on for size.  I think you need to delve into hard/soft acid/base theory for a complete satisfactory answer.

http://www.chemicalforums.com/index.php?topic=4894.0
http://chemed.chem.purdue.edu/genchem/topicreview/bp/3organic/acids.html
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch11/lewis.php
http://www.meta-synthesis.com/webbook/42_acids-bases/lewis.html
http://www.meta-synthesis.com/webbook/43_hsab/HSAB.html

[minimal]

Hmm ok.  I just looked up http://www.meta-synthesis.com/webbook/13_lab-matrix/LAB_matrix.html (btw thanks for the meta-synthesis.com reference, I like the site).  It says that Na+ is a Lewis acid.  But I think I understand the concept a bit more now...
Na+ is a lewis acid, as Cl- is a lewis base.  Just as H+ is a lewis acid and Cl- is a lewis base.  But the difference is because the bond is ionic?  There is technically a complex where you cannot say any particular Na+ is bonded to any particular Cl-, thus its ability to be an electron acceptor is muted because there is not a particular bond that can be broken in order to make Na+ the electron acceptor it could be?
If that is the case, what would the behavior of a salt be as it is heated towards and into vaporization?  Would you lose Na or Cl preferentially, or would it behave as a compound?

edit: but now that I look it up (and think about it).  HCl has to be ionic, even though it is conventionally drawn covalently, because it dissociates into ions.  I'm ultimately failing to see the distinction between salts and acids and bases.  OH is electron donator, Cl is electron donator.  Na forms ionic bonds to both, and is an electron acceptor. 
Could this have to do with solvents?  HCl in water will produce H3O+ (covalent) and Cl-.  NaCl in water will not produce NaH2O+ because of bond length/steric bulk of the Na+ cation, and that O is not as electronegative as Cl so that it would not form an ion with Na, as Cl does, making it the more stable option?

edit#2: Ok I think I finally figured it out.  It's the difference between how in a lewis acid the acid is H+ while in bronsted theory the acid is the HCl molecule, or anything that is a proton donor.  The lewis acid depends upon the strength of the base and such.  So then dissociation constants and all that are regarding bronsted acids only - unless the specific base is noted and only compared to the same base?
Ok, so finally, what does this mean of salts then...according to Lewis theory a salt is an acid and base mixed together.  How does that make HCl different from NaCl?