You can accomplish this already using a few tools already at your disposal, but it's going to be an enormous file unless you use subroutines or write a macro to do the "heavy lifting".
The width of your path will be determind by the OD of your tool plus the offset needed to implement a circular interpolation (most controllers require a certain amount of lead-in for engagement to work properly, this is generally a percentage of the tool OD)...your controller might work with as little as .025" lead-in, or need as much as .100"...this plus your tool OD will determine the actual width of the slot.
After that, it's merely tricking your controller into seeing the "line" as a bunch of overlapping/advancing arcs, that your tool will be ramping into and away from, at an appropriate chip-load, speed & feed. This is where your subroutines or macro comes in, because at each call-up you don't want your machine to stop, but merely to continue into the next cut. Your code has to execute repeatedly as many times as it takes to complete the length of cut...it could be 100 call-ups, it could be 1000 call-ups.
It's, for lack of a more elegant name, linear corkscrew milling. Kinda like having a tornado on a leash