You really have to just play with this recipe to see what suits your tastes, but here's where to start off at:
2 cucumbers, sliced and quartered
1/4 c. vinegar
1/2 c. olive oil
parsley to taste
onion powder to taste
salt to taste
Mix it all together and serve cold. You can play with the amounts of vinegar and oil but you want to keep the oil amount double however much vinegar you use.