Can I use lightning for ERC-20 (Ethereum coins) Just finished setting up my lightnig node. It is awesome!! Does anybody knows an implementation or documentation that explains how to make it work on rinkeby or ethereum mainnet?
Short answer there is non. 

The Ethereum people have tried to create the Raiden Network which is supposed to be their offchain solution. As far as I know (thought not 100% certain) They use ERC-20 tokens to create payment channels but the network cannot transfer ERC-20 tokens. The Lightning Network Protocol itself is currently only designed to transfer an amount of currency.

One of the reasons is that the onions of the transport layer are limited in size. 

If you are interested in transfering smart contracts or tokens you might want to look at the RGB Project by BHB Networks. This group tries to create colored coins (which are basically tokens) on top of bitcoin in a way that this is compatible with the Lightning Network. However this is work in progress and will - according to one of the main developers - take probably years before it is ready to use.