First off, there is NO STANDARD TUNING for these instruments. They can be found from the tip of South Africa all the way north to Ethiopia. If there's a dozen ways to tune a guitar, there must be thousands of ways for a kalimba.

I lived for a while in what was then called "Rhodesia" (Zimbabwe nowadays), and the Shona tribe made what are arguably the best Mbira on the continent. You could tell what family made one by how it was tuned. These are VERY complex. For more information, read the book "Soul of the Mbira" by Paul Berliner.

When someone asks me how they should tune their kalimba, I ask how they are going to be using them. If you want to play folk songs on them, go for the standard diatonic (do-re-mi-fa-so-la-ti-do) tuning. I usually go for a G major (G A B C D E F# g). If you want to jam with a blues guitar, a pentatonic scale will let even a beginner lay down a killer riff flawlessly.

I usually play on my own, or with drum, voice and hosho (zimbabwe-style maracas) so I can use a non-European tuning for a more authentic sound. When I'm alone, I often bring out the Sansula made by Peter Hokema in Germany. The tuning is Japanese Akebono, and the sound is MIND BENDING in the good way. Look for Sansula videos on YouTube.