Black eggs (?) on my rocket

Hi all!

A novice gardener in South Africa here, needing some help please.

I just moved to a new place and have a nice little garden space and plan to grow a variety of greens and other small food plants.

My young rocket plants have been rather savagely eaten, see attached pics, and I figured it was slugs, so am trying egg shells and orange peels and will put down some ash as soon as I transplant them to a bigger bed.

I looked around for caterpillars but no luck yet.

But as of a few days ago (sidenote: here in Cape Town we're in early spring) I saw a whole bunch of small dark dots on the leaves, they don't seem to be bugs (and no jumping so I guess not flea beetle). 

My plan is to transplant and surround with ash and eggshells, maybe spray down with pepper water or tobacco water and wipe off the leaves to get rid of the black dots. (they come off rather easily.)

Does this sounds right? Any ideas, tips?

Thanks a million!