Have you tried removing the iPhone app for the Watch app you want to remove? I have not, but doing that for a non-Apple app would remove the corresponding Watch app.
As others have said, no, you can't at this time. Maybe someday though.
Also, please don't call it an "iWatch". The proper name is "Apple Watch". thank you
Try putting your favorite apps in one "corner" of the pile.
Or cluster them around the Clock "app" in the center of the screen.
Back when the AW was new, people were posting screenshots of their app layouts. Generally, similar apps were grouped together in different sections, with the most-used apps getting the six prime spots surrounding the clock face (which always appears dead-center after you press the crown).