Take a look at the blue sky in the background and the color of her hair. In the Swami Vivekananda, the concept of infinity is considered blue. Take the air and water, for within the space of our hands, it is colorless, but in a vast quantity it is blue. Tenshi is shown to represent infinity, as she to is of the sky. As to the corndog to her, the Route 66 sign is to the sky. What of the tiny stretch of road to the vastness of the heavens? But without that land, the heavens would not be.
So as it is, you see the Heavenly consume the Earthly. Not out of pleasure, as we can see from her expression, but of necessity to understand the realm she observes from up high. But we see it as something of joy, for we too know that the divine are as of us. This is perhaps a commentary of the immaturity of Tenshi Hinanwi, who still has a physical body unlike truly enlightened beings. But it could also be a commentary of the unwilligness of humans to see gods (at least the important ones) as anything but in their image and why the gods so often take human form. This is represented even in the game afterwards, Hisoutensoku (Unpercieving of Natural Law). Unlike its predecessor, Gakutensoku (Learning of Natural Law), Hisoutensoku is considered blind to it, as it from a land without logic. In the utter contrast of “Tenshi Eating a Corndog”, we see through the eyes of Hisoutensoku.
This is the true symbolism behind “Tenshi Eating a Corndog”: That our perception is constrained by the laws that invisibly govern over us. Pierce the veil of illusion, and see why the mustard intertwines with the ketchup.