Where did you get the seeds from were they store bought or saved? To me it doesn't look like anything is eating them it looks more like a mosaic virus. I will say that sometimes when aphids suck the juices out of plants they cause deformed leaves, but I don't think that is the cause. If other people on here think it could be a mosaic virus as well I would destroy those plants and start over. Typically there is discoloration associated with mosaic viruses so maybe that isn't what it is. Sometimes seedlings just have a few deformed leaves initially and then they seem to correct the problem somehow. I have let such plants grow only to be very disappointed with them. Whatever the cause those are examples of plants I would thin out.

Hmmm, it looks to me like the damage is old and the new leaves look OK. Did you have heavy rain or windy weather when the damage first appeared? Sometimes tender leaves can be beaten rather severely by such meterological happenings. A little mulch may help that, otherwise just wait for the new leaves to get bigger! As someone else noted elsewhere, there seems to be a lot of plain old weather damage appearing on the forums this year!

Cheers!

Sunni