Have you started looking at SQL Server 2012 (and 2014 of course) SSAS Tabular model? If you are used to Multidimentional, it is a bit different. However, if you are more used to the database engine parts of SQL Server I belive you will find it more intuitive to get to grips with, and start to understand the concepts of.
If you have started using it, I would guess that one of the reasons would be that you have heard about how lightening fast it is. So, if it’s that fast, why would you ever need to consider performance tuning SSAS Tabular model? The answer is simple: Today’s fast is tomorrow’s slow, and your data will multiply faster that you can imagine 🙂 So, get ready to start tuning!
To get you started, I would recommend this great document by Microsoft that you can download here.