Six short lines, and a strange, delightful image at the center: the speaker "dines on paint." It's not a meal in any ordinary sense. Paint here seems to stand for color, and the poem imagines taking color in so completely that it feeds the eyes, and the self, from the inside.
The payoff comes in the second stanza. The speaker is glad "to see / once again / at night." The title, "Night Vision," suggests that darkness has been a kind of blindness, or at least a loss of color and detail. Eating paint restores that sight, as if the speaker has swallowed their own light source. Judging by the wording, this could be a literal painter's hunger or a more figurative longing for imagination to work when the world goes dark.
The mood is quietly joyful and a little surreal. The brief lines and gentle breaks mimic small, slow bites, and the phrase "in great joy" gives the whole thing a feeling of relief and wonder.