Fitting a throttle

I have a new Kudos City, and while I am not to keen on riding the bike I have decided to keep it for now,main problems are I find it a bit to big for me,but hopefully I can sort that by changing the sprung seat post for a solid one and fitting a different seat, this will then lower the riding position for me. I also dislike the way the motor only kicks in when you start peddling,then cuts out when you stop, I understand why has to,but would much prefer to control it by a throttle. Can I fit one to this bike and not use the pedal,if its possible how easy is it and what bits do I need to buy. Thanks