With the first release of professional salaries by a League of Legends team (Ember), we are going to start tracking compensation. In addition to publicly available information, if any professional (LCS or Challenger Series) player wishes to submit their information, please email firstname.lastname@example.org or contact the site creator on Reddit: /u/uncgopher. You will need to use a verified account in order to submit this information.
Also, for players who want to submit their information anonymously, we can withhold as much information as you want (though we encourage you to at least let us display your server). In addition to having the player name be 'Anonymous', we can also provide a salary range instead of an exact amount (similar to Glassdoor). Players in North America are specifically protected from employer retaliation due to revealing their salary by the National Labor Relations Act.