“Dainichi-nyorai’s themes are beauty, cleansing, protection, spirituality and weather. Her symbols are lilies, gold-colored items and light.
This light bearing Goddess comes in answer to the the Japanese people’s prayers for sunlight. Having all the sun’s power, Dainichi-nyorai embodies pure goodness, Her name meaning ‘great illuminator.’ With this in mind, call upon this Goddess at midyear to assist your quest for enlightenment and keep the road ahead filled with radiance.
In Shinto tradition, today marks a time when people gather lilies as an offering to entreat the Goddess to stop flooding rains. This is really a form of weather magic. If you need rain in your area, burn a lily; to banish rain, wave the lily in the air to move the clouds away!
It is customary to anoint one’s hearth (the stove) today with lily (or any floral scented) oil. This welcomes Dainichi-nyorai in all Her radiant goodness into the heart of your home an the hearts of all those who live there. Wear something gold while doing this, or decorate your kitchen with a yellow or gold-toned candle. When you light the candle, whisper Dainichi-nyorai’s name so She can live through the flame, warming every corner of your life.
By the way, if you feel adventurous, lily buds are edible; they have a nutty taste. Try cooking them in butter and eating them to internalize all the positive energies of this festival and the Goddess.”
(Patricia Telesco, “365 Goddess: a daily guide to the magic and inspiration of the goddess”.)
During my research for today’s entry, I found that Dainichi-nyorai (also seen as Vairocana, Vairochana or Mahāvairocana) was not a Goddess at all, but a celestial Buddha who is often (e.g. in the Flower Garland Sutra) interpreted as the Bliss Body of the historical Gautama Buddha. In Sino-Japanese Buddhism, Vairocana is also seen as the embodiment of the Buddhist concept of shunyata or emptiness. In the conception of the Five Wisdom Buddhas of Vajrayana Buddhism, Vairocana is at the center. His consort in Tibetan Buddhism is White Tara (for every dhyani Buddha there is an affiliated female Buddha in the Tibetan Tradition).” 
Upon further research, I found “Dainichi (lit. ‘Great Sun’) is worshipped as the supreme, primordial sun Buddha. Under the syncretic doctrine of honji suijaku, the Shinto sun Goddess Amaterasu was considered a manifestation of Dainichi Nyorai. The term Nyorai (lit. ‘thus-come one’) is an epithet for the enlightened Buddhas that occupy the highest rank in the Japanese Buddhist pantheon.” 
Calling Dainichi-nyorai a Goddess was too much of a stretch for me; but at least I see the connection between between Dainichi-nyorai and a Goddess – the Goddess Amaterasu. “With the identification of the Dainichi Nyorai with a Shinto kami so began the syncretism of Shintoism and Buddhism.” 
Facts-about-japan.com, “Religion in Japan“.
Wikipedia, “Dainichi Nyorai (Enjō-ji)“.
Hoffert, Brian. North Central College, “Shingon Buddhism“.
OnMarkproductions.com, “SHINTŌ GUIDEBOOK“.