The classic is an anchovy or sardine sandwich on crusty French bread. Top it with sliced cucumbers and tomatoes and wrap it up in foil. If you can make a fire, you can heat it. Then sprinkle with olive oil before eating. You can use greens or not.
Pickled foods are good for picnics.
People get scared because they think of pickles off the shelf. But you can just take some rice wine vinegar and sugar, boil it, and pour it over cut vegetables. Marinate them anywhere from three hours to three days. Pickled foods don't always work very well with wine. You can also marinate with yogurt.