There is no 'ctrl + something' to do that. If you followed the tutorial you would understand... or maybe you can't understand English.
Anyway,
Console =
Sega Genesis. Not SNES.
Emulator =
GensKMod. Download it here:
http://retrogamezone.co.uk/tutorialvideos.htmHow to rip from Sega Genesis games:
First method- Run the game;
- Pause the game with Esc; advance frame by frame (Frame step) with Shift + Esc;
- When you want to rip:

go to CPU, Debug, Layers;
- when you press Layers:

you get this window.
- Disable the layers you don't want and enable the "Colour Key" (magenta BG colour).

You can now get the rips the way you want.
Second method (copied from one of my posts in other forums)- When you want to rip something stop the game (with the Esc button on your keyboard);

- usually you can rip sprites with screenshots (nothing wrong with that) but sometimes it becomes really difficult to get the sprites, like in this case; so now we go to the CPU menu, then Debug, Genesis, VDP - sprites:

- when you click it, a window will appear:

-
do not dump the images with the dump button! Instead use the Print button on your keyboard (of course you'll have to paste it in an image editing program like Paint) and use the smaller image in the window (pixel perfect). The one in the left under the word "Priority", if it wasn't clear.
Also remember that you're not going to get the sprite, but
pieces of the sprite in that frame that
you have to put together.
Another thing to keep in mind:
the pieces have a slightly different palette (they may look the same as your rips when you get them from screenshots but they're not).
Third method (written by Enscripture in Mugen Fighter's Guild)Look up GSavestate. Pause the game when it's at the frame you want, make a savestate with Genecyst and load it in GSavestate. You can get the full frames with this, and backgrounds and other stuff.