Chop cucumber and raw mango into medium big chunks.
Grind 1 cup coconut with ½ tsp cumin, 2 tsp All purpose Chilli Powder, ¼ tsp turmeric powder to a smooth paste by adding enough water. Transfer chopped cucumber, raw mango, sliced green chilli, crushed ginger, turmeric powder and salt to a cooker. Add 1 cup of water and keep it for a whistle.
When cooled down, open the cooker and add grinded coconut mixture along with ¼ cup water.
Give it a nice boil.
In another pan, add oil, splutter mustard, fenugreek, red chilli, small onion and curry leaves.
Pour into the gravy, and cucumber curry is ready to be served with rice.