Update..!
Given the recent release of Avengers: Infinity War, it's revealed that
Red Skull was in fact teleported, and is alive on the planet Vormir. According to Red Skull, he was banished there by the Tesseract.
This would also explain why the Tesseract stayed on Earth, instead of going with Red Skull.
Did the Red Skull actually die or was he sucked to another space dimension? Because the Tesseract is later revealed to be a Space Infinity Stone
I just watched that scene over and over and over, starting and stopping right when he disappears, and, guess what...
he teleports!!
If you start the video below at 3m27s and stop it right after it hits 3m28s -- so, literally one second -- and you do this over and over and over, then you'll be able to see the elongation of Red Skull's head and body (but mostly head) as he's being teleported. This kind of elongating behavior is very common with beam teleportation.
I tried my best to capture the process in the following screenshots, and made sure to keep the tops of the shots just above the frame, to maintain a constant point of reference --
Top: remaining clothes are disintegrating as Tesseract continues to "charge up". Red Skull maintains body form.; Bottom: Close up of Red Skull inside the Tesseract beam, being elongated during initial teleportation.
When considering the second and third screenshot on the bottom row, Red Skull's head is clearly distinguishable, as well as his neckline (you can see his head a little in the first shot). And then, when comparing shots 2 to 3, the head and neckline elongates, which is an indication of him teleporting.
Just after those frames, the camera then follows the already fully manifested Tesseract beam upwards, as if it were focusing on Red Skull.
IMO, if Red Skull had actually been killed by the power of the Tesseract, he probably wouldn't have elongated like this, and the camera wouldn't have behaved as such; but instead, Red Skull would have simply disintegrated completely, and/or blown up (or some other grand gesture, other than just disappearing in a beam).
All of this being said, I wouldn't be surprised to see Red Skull in a future Marvel film.