I do not know of a command to delete a single frame.
The way I would do it, is to enlarge (expand) the time line to where I can see the marks for the individual frames. Then put the CTI on the mark at the beginning of the frame and do the scissors. Then set the CTI on the next mark and scissors again. Select (highlight) the single frame and press DEL.
The scissors will net be that difficult if you expand the time line enough to see the frame has marks.
Another alternative is to scissor at the beginning of the clip and use the single frame advance button at the bottom of the monitor window. Three frames would be three clicks, then scissor.