Ensure all your components are located somewhere under your public directory.
Include an imports.html file anywhere available to the client, that contains the html imports that would normally go inside your <head> tag.

<!-- Core Components -->
<link rel="import" href="/components/core-animation/core-animation.html">
<link rel="import" href="/components/core-animated-pages/core-animated-pages.html">
<link rel="import" href="/components/core-animated-pages/transitions/slide-from-right.html">
<link rel="import" href="/components/core-drawer-panel/core-drawer-panel.html">
<link rel="import" href="/components/core-pages/core-pages.html">
...

<!-- Paper Components -->
<link rel="import" href="/components/paper-dialog/paper-action-dialog.html">
<link rel="import" href="/components/paper-dialog/paper-dialog-transition.html">
<link rel="import" href="/components/paper-input/paper-input.html">
...

Running your app in development as usual will result in the contents of imports.html being added to your <head> tag, resulting in multiple subsequent HTTP requests (good in development - debugging).
Running meteor, meteor build, modulus deploy, etc with the VULCANIZE=true environment variable set will result in all your html imports being vulcanized or concatenated into a single html import (good in production). The resulting file will be called vulcanized.html, which will be automatically added to your <head> tag. For example, VULCANIZE=true meteor, VULCANIZE=true modulus deploy.
Setting the CDN_PREFIX environment variable will prepend the string to the beginning of the file path that is inserted into your HTML's <head> tag.