It's good weather for going out and wandering about the place at the moment. As anyone with half a brain knows, this means you have to take a rucksack full of beer with you, and a delicious snack. This covers the second part.
It's basically a massive sandwich from Nice, and nice is what it is.

Tinned tuna
Hard boiled eggs, sliced
Tomatoes, sliced
Some sweetish onion, sliced - maybe a white one or a red one. Spansih onion is also OK, but the little German onions are too strong.
Basil leaves
Black olives, pitted
Olive oil
Some vinaigrette (any really)

Get some big bread rolls, or even a baguette. Slice them open lengthways, then remove most of the actual white bread with your fingers. Rub the inside of the bread with a cut garlic clove, then paint it all with loads of olive oil. Chuck in a few basil leaves, then layer the eggs, onions, tomatoes, and olives insode, top with the tuna, and a little vinaigrette. Close up the sandwich and press it. Basically you need to cover it with something like a baking tray or big dish, and wiegh it down, with bags of beans or flour or something. Leave it pressed for about 15 minutes or so, then wrap it up, and take it out on your walk. Or just eat it right there and then. Don't give any to your dog. He'll just wander off with it, and then only eat certain bits. Idiot dog.