Both hands are constantly expelling energy out and taking energy in through the major energy gates located in the middle of your palm.
Neo-Pagan/New-Age educators like to teach that the right hand is the "projecting hand" and the left hand is the "receptive hand," but in actuality each hand does both. Acupuncturists, Qigong masters, Tai Chi teachers, doctors of Asian medicine, Reiki practitioners, etheric healers, etc., etc., all use both hands to direct and collect energy.
Many people do have hands that are slightly more "projective" than the other or slightly more "receptive" than the other, but it's usually only a negligible difference. Now, you can train your energy gates to do different things - and certainly your intention direct your energy - so if you really truly believe that one hand is dominant, it very well may be because you ordered it so.