How are these RC values calculated in this buck converter?
After looking at the dataheet these components form a low pass on the output of the current controller. They are components that are not meant to be included in the design process. The values of these components are selected by LT to keep the current control loop stable while still have a fast enough transient response. I would just use the values suggested by LT and if I run into stability problems during prototyping, I'd give them a call.