Probably in the cress family, perhaps a bittercress eg Cardamine hirsuta? A picture would be enormously helpful. When I first saw something like that in my yard I thought it was Arabidopsis (thale cress), an experimental model plant I worked on for years and I was excited to see it in the wild. (it wasn't)

Getting rid of it? Unlikely short of a multi-year chemical warfare campaign. Just not worth it. Plants in this family make a lot of seeds and flower long before you're thinking of working in the garden.

No, definitely not that. I will try to post a pic later.