1. Scrape the yogurt into a bowl.
2. Peel the cucumber, slice lengthwise, and scrape out the seeds with a spoon. Dice the cucumber into bite-size pieces. Core the tomato and dice the tomato into bite-size pieces and add them to the yogurt along with the cucumbers.
3. Chop the cilantro and add most of it to the bowl, reserving a little to garnish the finished raita. Chop as much, or as little, of the chili pepper as you’d like to use and add it to the mixture.
4. In a mortar and pestle (or with a hammer in a sturdy zip-top bag), crush the cumin seeds to a slightly coarse powder. Stir the ground seeds to the raita, along with masala powder and salt (to taste).
5. Sprinkle the top with additional chopped cilantro. Serve at room temperature, or chilled, alongside a favorite Indian dish or as a salad.