Trim the greens from the radishes and trim into 1-inch pieces, removing any stemmy parts. Trim root and stem off radishes and quarter them if large or halve them if small.

Heat oil in a large frying pan over medium-high heat. Add radishes and season with salt and pepper. Add radishes and cook without moving for a few minutes or until a nice golden crust forms on one side. Stir and cook a few minutes more. Add greens, sugar, and vinegar and cook a few minutes more until radishes are glazed. Sprinkle with a little more salt and serve.