There is a fairly easy way to assign textures to a single face- you might want to try this (based on the assumption that is a poly cylinder btw).

I highly recommend the tut, as it shows you how to lay out the UVs for a whole object, but this is an easy basic way to assign the material for temp use.

First select the top face of your cylinder and go to

polygons/texture/planar mapping

and select the box next to the entry. You will see some options- change the direction of the mapping to the y axis as on the screenshot attached- that's because the top of your 'watch' lies along that axis and Maya needs to know which direction to make the textures in.

Select that then hit apply. A box will appear lying flat across the top of your cylinder. That's showing you where the textures are going.

If you then open the UV texture editor (window/uv texture editor) you will see those faces in the window. From there you can take a 'picture' of the face to your image editor to put the clockface on to ensure a perfect 'fit'.

Choose select/convert selection to Uvs (you don't need to lay anything out for mapping one face) then polygons UV snapshot. Save the image in the location of your choice and then open it in your image editor, paint on your clockface and save.

Then open the hypershade and create a new lambert by clicking on the lambert picture in the left window. Clicking on that new lambert (don't change lambert1 the default one) brings up some options- if you choose the box to the right of the colour bar you get some further options on assigning different materials to the lambert- choose to assign a file, browse for the clockface you created and select it.

You should now have a lambert material with your clockface on. Select the top faces on your cylinder and right click on the lambert and choose assign material to selection.