Heat oil in a small saucepan and then add all the spices. Cook until the seeds start to pop.
Add the chopped tomatoes and cook for two minutes, until they begin to soften and reduce.
Add the chopped cucumber and cook for a further three or four minutes, until the cucumber begins to soften but still retains some of its crunch.
Notes
The original recipe called for an unspecified quantity of water to be added with the tomato, but I found my tomatoes added enough liquid on their own, so I didn't add any extra.