Help with re-wiring a two circuit outlet with one controlled by switch
Yes, it looks like this is a switch loop type wiring arrangement.  The black in the /3 cable brings "hot" from the breaker panel.  It then goes to the TAGGED/MARKED white wire in the /2 cable, which is the always-hot wire going up to the disposal switch. 

The switch does (or does not) connect the TAGGED/MARKED white "always-hot" wire to the disposal's "switched-hot" wire, which is the black wire.  That goes to the disposal outlet.  

Code now requires several things missing from this installation.  Partly that is because this installation is a "multi-wire branch circuit" (MWBC), two circuit hots sharing 1 neutral. 


The white wire must be tagged/marked a color (or black) to indicate it is in use as a hot wire.  
The two circuit breakers which power the disposal and dishwasher need a handle-tie so that when you shut one off, the other also shuts off.  The handle-tie must be UL listed specifically for the breakers. Finding this correct handle-tie is often hard, so we recommend simply replacing both breakers with a 2-pole breaker.  Such a breaker inherently has a "handle tie" built in from the factory.  
Your situation might be grandfathered, but if not, the dishwasher needs GFCI protection.   The only way to accomplish this, given your circuit layout, is a 2-pole GFCI breaker in the service panel.   This will also take care of the above issue, and provide GFCI protection for the disposal as well.  
It is vitally important that this MWBC not be fed off a duplex/tandem/double-stuff breaker (2 breakers in one breaker space). People often confuse double-stuffs with 2-pole breakers, but the giveaway is that the handles are not factory tied.  


If you need guidance selecting a suitable breaker for your panel, ask - we have experts on that subject!  Do not just slap in any random breaker into any random panel; they may seem to fit but will arc and damage the breaker and panel.