Flushing the writes to disk wouldn’t help actually. It would need to go write zeros on the previous location of the record on the storage subsystem. That would not be performant at all.
For straight up deleted records to not come back when using the Community Edition, one would have to erase the storage upon restart.
The alternative would be to leverage expirations, while making sure the time when a record will expire is not shorten.
This article explains the different situations when records are loaded upon a cold restart:
(Of course, the other option would be to use the Enterprise Edition for development. Hopefully something Aerospike will allow with a special license in the near future).