Keep other ingredients for chutney ready as shown in below picture.
Heat a kadai and dry roast cumin and methi seeds.
Add 1 teaspoon of oil and fry red chillis.
Add all these ingredients to mortar pestle and crush into a rough paste.
Meanwhile, add another teaspoon of oil into kadai and cook chopped cucumber pieces. You can add water if these don't get cooked with their own water content. Cooking time depends on cucumber. It took around 10 minutes for me.
Add cooked cucumber pieces to mortar pestle and mash it into a rough paste.
Take all tadka ingredients and put tadka in remaining oil. Add tadka to above chutney mixture and chutney is ready to serve !!