Cut cucumber in half lengthways and using a teaspoon, scoop out the seeds. Grate the cucumber using the Thermomix cutter (I like to grate thickly for texture) or a box grater. Squeeze out excess water and add the cucumber to a bowl.
Add remaining ingredients to the bowl with cucumber and mix well with a fork. Taste and adjust seasoning with salt and lemon juice. Add 1/2 tsp of sugar if you feel it is needed.