Major Description
I have looked a little bit into where the time is going when starting MiniAccumuloCluster, but I have not looked into how it could possibly be sped up.
First a ZooKeeper server is started and then Accumulo initialize is run. This takes about 1 second. After this a master and tablet server are started. It takes ~2 seconds from the time the tablet server starts until the root tablet is assigned. I think these two places are where the bulk of the startup time is currently spent.