Just a note, don't pick your dandelion greens in the dog park. Seriously, I saw some woman doing just that.
But dandelion greens are fine to eat, as long as the greens are young. Older greens are too tough.
So pick the young dandelion greens, heat oil in a frying pan, and throw in the washed greens.
It is worth noting that a human can survive on weeds and oil. Not weeds alone, the oil is essential.