Obviously a clockwise rotating propeller will have the opposite effect. The hand throttle normally includes a cut off switch and the electric start button, if fitted. Mouth-throttles are sometimes used, and incorporate a mercury switch to cut off the engine when the throttle is dropped. The ability to start the engine when standing up ready to go is also very useful. Not as easy as it may sound.
Most engines have a minimum electrical system - just enough to provide a spark.
Electric start batteries are typically Ni-Cads, charged from the mains. Although it may be possible to do in ideal conditions, in practice it doesn't often work and can even be dangerous if back-firing. Various types of de-compressors help with the starting of engines, manual or automatic. Some paramotors have centrifugal clutches, meaning that only when you apply power will the propeller rotate. The idea is that a light flexible cage can be used, allowing the odd crash without bending the cage and exploding the propeller.