How to remove cinema mode on watch

If you mean remove the Theater Mode button in Control center, contained in this link is the following --> Use Control Center on Apple Watch - Apple Support

Remove Control Center buttons

You can remove the buttons in Control Center by following these steps:

1. Touch and hold the bottom of the screen, then swipe up to open Control Center.
2. Scroll to the bottom of Control Center, then tap Edit.
3. Tap  in the corner of the button you want to remove.
4. Tap Done when you’re finished.

To restore a button you’ve removed, open Control Center, tap Edit, then tap  in the corner of the button you want to restore. Tap Done when you’re finished.

Swipe up on the watch face and tap on the icon that has 2 masks;