This can be easily achieved by using any tier of artillery, then hitting distant targets until you get a kill.
I used the Tier III French Artillery as it has decent range and does decent damage.
Otherwise a Tank Destroyer works, just sit back and snipe targets spotted by your teams light and medium tanks. Having camouflage modules and hiding in bushes helps lessens the chance of you being spotted by the other team.
You will know if you are spotted, as "Detected" will appear in yellow letters in the bottom left corner.