After signing up for the challenge you are presented with the first challenge, shown below. You're presented with the first challenge file which is a password protected 7-zip file. The goal of this (and every) flare-on challenge is to find a unique flag value, in the form an email address ending in "@flare-on.com".
Once we expand the 7-zip archive with the password "infected" we are left with a Java binary or .JAR file named "MinesweeperChampionshipRegistration.jar". Basic file metadata is:
File Type: JAR
Size: 1.1 KB (1111 bytes)
Java is compiled bytecode, so my first thought was to open it up in JDgui, an exellent free Java decompiler. It breaks down Java .class files into source code allowing for quick analysis with out the need to inspect .JAR files dynamically. Once doing so the answer was very easy to spot!
To summarize, the first challenge was very easy. For a new malware analyst all one really needed to know was that it'd be a good starting point to decompile "MinesweeperChampionshipRegistration.jar". On to challenge #2, which we know will not be nearly as easy!