With Glass you can launch an app via the \'OK, Glass\' menu and it seems to pick the nearest match unless a command is miles off, and you can obviously see the list of comma
You can take advantage of the disambiguation step that occurs when multiple Activities or Services support the same Voice Trigger: simply have multiple Activities or Services in your application support "show me the color" as the voice trigger and label them with the color options.
Your manifest would look something like:
Those Activities or Services would only be used as a "trampoline" to launch the main logic of your app with the color selection.