One of my favourite and really really simple salads is a cucumber salad with yoghurt & dill sauce.
Can't give you quantities as I jsut chuck things together to taste:
Thinly sliced European Cucumber (the long skinny ones, or Lebanese would work, too). A mandoline type slicer is really handy for that.
Dressing:
plain yoghurt (I use mostly greek style yoghurt)
salt
freshly crushed garlic
chopped dill (generous)
a dash of red wine vinegar (depending on how acidic your yoghurt is)
a little olive oil
combine all in a bowl with a small whisk or fork until creamy
Mix with the cucumber and let stand in the frisdge for 1/2 hour to let the flavours develop

This is really refreshing and goes well with greek dishes or comfort foods like lamb stew. And oh so simple.

Sasa