Reiki is a Japanese technique for stress reduction and relaxation. Reiki translates to universal life-force energy. This life-force energy, is in all things (like the Goddess and God) and can be guided to anyone, anywhere, and anytime.
It has been taught that, unless you are attuned to Reiki by a Reiki Master Teacher, than you can not practice Reiki. I first learned about Reiki around fifteen-years-old. My Wicca teacher, told me that because Reiki is universal life-force energy, it did not need an attunement especially when you are a witch.
People who practice working with natural elements, have at their disposal, raw universal life-force energy. When a witch calls upon the elements and gives them their situation, this could be even more powerful than Reiki. However Life-Force Energy, or Chi, can be found in all things.
Once my child mind could comprehend this, I began creating a Self-Healing Ritual using the air, fire, water, earth and Reiki.

To begin, start by cleansing yourself with smudge. When you have covered your entire body, go to the area that needs healing.
Let the smoke cleanse the area and repeat out loud;
From the air and fire, I summon healing power, to heal me now in this hour.
Reiki heals all things, Reiki heals me, Reiki heals me, Reiki heals all things.
Continue to focus on the area that needs healing, as though it was already healed.
Next mix three pinches of salt into a cup of water. Splash four times the water on the area that needs healing using your pointer and middle finger. Repeat out loud;
By water and earth bless me, heal my pain so I am free.
Rub that area in a clockwise circle while repeating out loud;
Reiki knows the cause of all illness and knows how to heal it completely. Reiki heal me, Reiki heal me, Reiki heal me, I am healed.
Repeat this process daily three times a day, until the area is healed.
Bright Blessings To Everyone!