How can I set the default format on Dynamic View theme and remove the menu option to change the format?

You can change the default format and remove the menu option to change the format.

1. Log in to Blogger.com

2. Click Theme->Customize->Theme->Select Dynamic View on the top and then the format that you want below the Dynamic View.

3. Click Apply to Blog->Back to Blogger

4. Click Theme->Edit HTML

5. Find the code below: (it should be around line#1637-1641)

<script language='javascript' type='text/javascript'>
  window.onload = function() {
    blogger.ui().configure().view();
  };
</script>

Then add 3 extra lines of code in yellow.

<script language='javascript' type='text/javascript'>
  window.onload = function() {
    blogger.templates().compile(
        blogger.templates().template("Header").raw()
            .replace(/{block:HasViews[\s\S]*block:HasViews}/,""));
    blogger.ui().configure().view();
  };
</script>

5. Click Save Theme and then view your blog.