Peel cucumber with vegetable peeler leaving strips of the skin unpeeled. Slice cucumber into quarters lengthwise. Slice off seeds. Halve each strip of cucumber again lengthwise and then cut crosswise into cubes.
Salt cucumber with ½ tsp salt and set aside for 30 minutes. Drain.
Slice baby boy tomatoes into quarters by cutting lengthwise and then crosswise. Set aside.
Toast cumin and mustard seeds in a pan for about 2 minutes. Remove and allow it to cool.
In a large bowl, combine all ingredients. Mix well.