http://en.lichess.org/OlRgXYke/white#43I played someone who really liked this opening, with both Bishops on a long diagonal. I manage a half-assed punishment for him, but I need to do better. I see a lot of weird openings like this since I'm new and I want to know how to counter them, any advice?
looks like u played some nice opening moves with some errors. Your pawn pushes were a little premature. U missed mate to take Q at the end, but overall you capitalized on your opponents bad moves. Keep learning and playing and practicing.
The thing about this setup with both bishops fianchettoed is that two outside pawns have to be moved, which does nothing for control of the centre (which should be your principal aim in the opening when you're starting out). So your opponent has lost some time, during which you can get a grip on the centre. Other potential disadvantages: the Bishops are attacking two different sides of the board, and uniting them in parallel could be difficult; their mobility is decreased.
There aren't any hard and fast rules for dealing with the setup, but with the above points in mind you should be able to get an advantageous position. Also: if a fianchettoed bishop is exchanged, it leaves a weakened pawn structure which you can maybe turn to your advantage.
one fianchettoed bishop can be frustrated by a pawn chain, which you didn't maintain. MackTheKnife's last point is espesily true when they castle behind the bishop.