Sure it is possible to use cucumber to make stew instead of tomatoes. I have prepared stew with cucumber and I've also made sauce with it.

If you are not particular about the colour but the taste of the stew and the food it will blend with, then you will like cucumber stew.

To make cucumber stew, you will also need other vegetables to blend with it
to enhance the taste.

I have two links to my blog posts here on Hive to share with you where you can find the cucumber stew and sauce. I will share it directly in the #foodtalk threadcast and tag you. Watch out for it.