One method :)
Close the seam by a line
Select this line and one half circle : Net Work
Same for other side

The half arcs circle must be not in one arc line so trim it in 2 arc lines
Network ABCDL in one time dont works!

Another solution :)
Copy rotate the hole circle
Trim keep Cylinder by this new circle
Rotate the new little circle
Union all ;)

Everyone, Thanks!
I was avoing to select all curves as was thinking it will erase my entire shape so i selected only those which formed hole.. - for inner trims it worked but not for the outer boundary trims

I'd better ask no more questions so that Michael had more time for MoI and possibly creating instances feature;))