If you have time, put the yogurt in a cheese cloth-lined colander and drain it in the refrigerator for at least one hour, preferably more. This will produce a thick yogurt, which when mixed with the cucumber will produce a thicker and less watery raita.
Squeeze the grated cucumber very well between your fingers to drain it. This prevents the raita from being too watery. Mix the cucumber with the yogurt, cumin and mint. Season to taste with salt and pepper.