I like to cut my cucumber slices a little more on the thicker side. This will be your preference. Here is how I cut mine.
Cut your cucumber in half, lengthwise. Take your half of cucumber and half it again. Now, slice the cucumber.
Dice your tomato. I like to use Roma or cherry tomato.
Thinly slice red onion
Combine your cucumber, tomato, and red onion in a bowl and add the remaining ingredients.
Mix together and refrigerate for 20-30 min to chill before serving.