Hello, has any one had success by using a radio control system/device to ignite the flash paper/string ( I actually trying to burst a balloon and can use the same method ) thanks for your help

Yes. It is a pretty common with multiple commercial offerings (mini pyro, incendio, etc.) But is there a specific reason to use fire? Or do you mean you just want to use the igniter directly on the balloon? If so, you can buy actual remote control balloon poppers as used in weddings, concerts, etc. Or you can use a limonene solution to pop a balloon after a certain time.

Sure - it's easy. You need a remote control unit, and some nichrome wire.