"This is when your foot hits the pedal full on to get the cymbals to hit together for that open sound."
Rimshot, if by that you mean the sound that you get without using sticks, where you hit the pedal hard and let up for that open sound, that's not what I'm talking about.
Imagine this sound, using sticks: Tch, Tch, Tch, Tchhhhhhh, Tch, Tch, Tch, Tchhhhhhh, Tch, Tch, Tch, Tchhhhhhh,
I'm talking about the sound that the high hats make between the 3rd "Tch" and the "Tchhhhhhh" (or starting with the closed hit for the start of the "Tchhhhhhh"), then the sweep before the hats are fully open.
Example: the first 4 bars of Steely Dan's "I Got The News", the hi-hat sound on the 4 beat of each bar.