As the summer is my favorite time of the year and that the beach is just 15 min bikeride away, I recommend Amager strand. Full of people usually though, but even so it gives a bit of an exotic touch to such a scandinavian city with the sea and the bright sand in the hot summer days.
Morgenstedet is vegetarian restaurant located at the free town of Christania, serves the best soups in town and other excellent organic food. Despite it’s name ”the morning place”, it’s also open in the evening.