Yup you sure can, although it means the droplets and combo colours will be black.
Go to the skin.ini file located in your skin's folder. Locate the "combo1" "combo2" etc lines under the [colours] section. Change the values of all them to "0, 0, 0" Press ctrl+s to save the file, then go back to osu! and reload your skin by pressing ctrl+shift+alt+s
Theres no other way to do this to my knowledge sadly.
The flashing light distracted me at first too, but don't worry, eventually it just fades into the background honestly (despite using 100% dim) and I don't notice it.
Hope this helps