This is one of the lunches that you can prepare ahead of time and it will stay good in the fridge for the week (not saying you have to eat it all week though :) )
This is a very simple wrap. You can buy tortillas at Coop or Migros. I wouldn't use the El Maiz ones as though they are wonderful, they are too expensive to use for this. I will however post the recipe on how to make tortillas when it is a little cooler and I want to have the stove on for a while. Today is all about no cooking (except microwave!)
The tortillas you are looking for at Coop are the Mission Tortilla Wraps. They are about 5 chf for a package of 6. The Old El Paso ones are ok, just do not buy the soft corn ones. They are horrible (especially if you are used to good Tex-Mex) Migros has Pancho Villa - and their flour ones are good (on sale this week!) but I have not tried the corn ones as the Coop ones put me off. (Also don't buy the jar guacamole - but that's also a post for later).
What you need:
Mayonnaise (or your Miracle Whip if you went to Konstanz)
Feta cheese - Coop or Migros
black olives - just slice them into little pieces. Adds a good flavor, but I didn't have any this time.
If you want, you could also add some grilled chicken. (precooked and cold for the warm days)
Slice the cucumber, dice the tomatoes and crumble the feta. Put the tortillas in the microwave for about 10 seconds, just to warm them enough that they don't tear when folding.
To make this easy for the week - just place you cut veggies in a closed dish and put in the fridge. If you have room, you can put them in separate ones, but since I don't, I combine them - in sections, not mixed up - and they are fine for 3 days.