BIG (48" x 35" w/o Frame!) Painting Couple w/Huge Hands - Artist?

I bought this from a friend today who found it in a storage locker won at a auction. It is BIG (48 x 35 not counting the frame!).
I can feel it's on canvas, but look at photo of back - you can see some threads from canvas but it also looks like it has a Masonite(?) border - isn't that unusual?
One thing - it's not signed anywhere that I can find? (photo of bottom is to show there's no signature)
I'm sure it's a good piece because it reminds me of a well known listed artist who was known for the large hands & feet on the people in his paintings - I can't remember his name but I believe he was central/south american. I posted a painting by him here before & the board knew who he was - does anyone recognize the style here with the large hands? (there's a framing company label on the back, so if I can find artist's name or the name of whose style it was done in, I can contact them & hopefully find out some more about it)
Any thoughts on it?
Thanks all for any help!

 

Oswaldo Guayasamin?

 

That's him! Thank you David Broom!

 

Interesting that it is wired to hang either vertically or horizontally.

 

Depending on how risqué you'd like the image to be!

Debora

 

I actually like this way better Debora - thanks!