Hi Radhesh,
The portfolio of low-power touch sensors use the human body as one of the capacitive plates of an electrical circuit. Capacitive sensors can also switch without contact due to proximity sensing or used with external plates connected to the device. I think this type of sensor are suitable for your application where the external plate is shaped as a continent. The sensors we have are, PCF8883 and PCF8885.
Hope you found them useful
Darío