Unaligned:
hello; tgere
foo; bar
yesthatis;fine
Select the first column of every line, run a "normal mode" command on each line:
<C-v>G:norm dt;
Aligned, I would probably use visual block rather than visual line:
one;two
thr;fou
fiv;six
Enter visual block, motion to ;, move down 2 lines, delete selection
<C-v>t;2jx