1. I have made a circuit operating from 220Vac/50Hz. It had capacitive supply to power up the microcontroller, which inturn controls the triac to switch 220Vac/50Hz to heating wire which is resistive in nature.
heating wire is resistive, which consumes 70W on 220Vac/50Hz.

2. Now I am checing some possibility if same circuit can work on 110Vac/60Hz. I think same capacitive supply can work(that I will check), but heating wire will not get heat up from 110Vac/60Hz, as it gets heat up at 220Vac/50Hz.

3. I am searching for some very light weight circuit which can do this. As this needs to be fit inside a handheld remote.
First thought was to use a transformer, but it will be bulky.

4. I think frequency does not affect much, as capacitive ckt will work fine & load is also resistive

5. Any ckt suggestion on this, On google I mainly found transformer based ckt or i am searching with wrong keywords

 

It sounds like you are directly switching mains. Be careful.

Just use an external 110V to 220V transformer as this device no doubt is plugged in anyway, it doesn't have to fit in the "handheld remote".
And check, if you are using phase control, at 60Hz the timing will be different from 50Hz. And the capacitive supply will have lower impedance too. Check your dissipation.

 

There is a Fairchild app AN-3006 also two Microchip app notes, AN958 and AN954.
Max.