Word for reverse blink
You are asking about "peek". That is to look quickly through the eyes, like a game of peek-a-boo. You don't have to use your hands though.
peek (pk) intr.v. peeked, peek·ing, peeks 1. To glance quickly. 2. To look or peer furtively, as from a place of concealment. 3. To be only partially visible, as if peering or emerging from hiding: Tiny crocuses peeked through the snow. n. A brief or furtive look. [Middle English piken, perhaps alteration of Middle Dutch kieken, variant of kken.] The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
If you are standing in the surface of the sun for a nanosecond, a peek would be the best you could do- although I wonder if Randall Munroe was seeking to emphasize how brief this "peek" would need to be. A peek can be several seconds, and as he suggests, even a nanosecond in the interior would be far too long.
To be fair, a nanosecond on the surface would warm you up, but not burn you - but several microseconds might. A peek is probably longer than that - I suspect he is alluding to "the blink of an eye" to underscore the brevity.
What I wonder is if a peek would blind you...