1) Slice tomato, cucumber, cheese and salami.
2) Spread tomato paste onto crackers.
3) Layer ingredients on top.
4) Season to taste.

Variations:
For the first couple of days Instead of tomatoes and cucumber, try sugar snap peas, mushrooms or capsicum. Also, consider avocado or hummus. After the first few days you will want to stick with lighter weight longer life toppings.

Try different types of ingredients on different crispbreads and biscuits! How many you need varies greatly, so try it out beforehand. Vary your ingredients to have a variety through the trip.  Tuna or chicken come in small 120g bags from your supermarket.