it seems getrawtransaction is not implemented indeed, and gettransaction doesn't allow non-wallet transactions?
a block explorer won't be able to show transactions then.. or eh..
Correct

slimcoin dev, could you add the getrawtransaction RPC method?
I think that's what that other developer asked about - but I don't know, not privy to their PMs

I actually have a partial database of the things you can get with getblock() (which were the source of the graphs), but yeah a block explorer should be able to work on the current state of the chain
and include all the usual info. Though personally I don't care for some 'Slimcoin rich list', it seems it's popular. Lord knows why.
how many coins exist?
Try
getinfo in the console.
getinfo
...
"blocks" : 31533,
"moneysupply" : 347488.41600500,
or via debug.log:
SetBestChain: new best=5d2a545e78a53fbb61b5 height=31533 trust=13321961995 moneysupply=347488.416005 nEffectiveBurnCoins=146778.282707