What beer would pair good with the food like caviar? I'm thinking about food which is salty, has a very strong flavor, but not spicy.
While pairing is generally a matter of taste and therefore no definite answers can be given, for salty food, strong food there are a couple of things to keep in mind.
Rich beers are likely to overpower whatever else you are eating. I would usually pair rich beers with moderate portions of rich foods. This doesn't mean that all salty foods would be out with something like this, but it is something to think about.
Bitterness is likely to help contrast a bit with the saltiness you are describing.
Obvious pairings to me would seem to include light, relatively bitter, hoppy beers. Something like an IPA, an extra special bitter, or the like. A lot of folks tend to find that bitterness in beer works, pairing-wise, like acidity in wine, so if you'd pair with a more acidic wine you may consider pairing with a more bitter beer.