For example, you can close "Dashboard" widgets while holding down the option key. I can’t find a way to close windows and/or exit an application directly from Mission Control. Though I'm looking for a keyboard shortcut or builtin solution ideally, Third Party solutions are acceptable so long as the application is simple and non-intrusive.
Here’s a screenshot if it’s still unclear what I’m asking.
Running macOS Sierra [originally asked Running El Capitan.]
Note: I see now that a similar question exists, but it’s five years old and still unanswered - hoping there’s a better solution out there…