Prepare the couscous according to package instructions. Chop the cucumber and tomatoes in small cubes. Once the couscous is done, loosen it up with a fork and let it cool down. Add the tomatoes and cucumber and season with salt, pepper and the lemon juice. Add the chopped parsley.
If you like you can add some chicken or ham into the salad. I used ham as that is what I had leftover in the fridge, but I think this would have been brilliant with feta or smoked chicken. (or both) You can also ad a splash of olive oil into it, which would probably have made it a little juicier but in the light of losing weight I opted not to.