Yes. The color of Map polygons and the polygons in a Canvas can be changed to whatever you need.
Here are several tutorials that might show what you to do to change a Map polygon's color
These examples will not show you exactly what you need to do in your app; they show different methods for changing a polygon's color. One of the methods should work for your Project.
You can possibly change the color of all the polygons in your app to another color by using the Any component blocks and looping over a List of the polygons.
If you write a more detailed explanation about what you want to do, someone can provide more specific advice. You might wish to share your Project aia or a Block image.