My grandma used to always make this for my sisters and I when we were younger. Its a very simple recipe that's crunchy, juicy, and perfect for summer.

Ingredients:
1 large cucumber [the fatter ones]
about a half a cup of soy sauce
1 tsp sugar
1 pinch of salt

Slice the cucumber length-wise, removing the seeds with a soon is optional, then slice semi-circles from the halves about a centimeter thick. The more thick, the more crunchy, but its totally fine to cut them thin. Place the cucumbers in a wide bowl and mix in sugar, salt, and then soy sauce. Mixing with your hands is more affective than with a spoon.
If half a cup of soy sauce is too much then just pour some out. I usually just eyeball the ingredients so my measurements aren't exact. You can always change up the measurements according to your taste.