You are right that in general you can't "pre-set" filters on metrics. However, once you've segmented or created a custom report with the filters that are available, you can apply metric filters from the advanced filtration area on any individual report.
However, for these particular two metrics, you can create a segment for the filtration you want. Instead of pages per session, you'll use the dimension
Page Depth in the Conditions panel of the segment builder. Page Depth is the number of pages visited in a given session, so it is for your purposes equivalent to pages per session.
A screenshot is worth paragraphs of description: First up, the Condition panel set to filter sessions to include Page Depth greater than or equal to 2.
Next, the Behavior panel set to filter Session Duration per session to be greater than or equal to 30 (seconds).
With that setup you'll get users who had at least one session in which they both stayed at least 30 seconds and visited at least 2 pages. If you change the options to filter users (or "per user", for the Behavior panel), you'll get users who had both a session in which they visited at least two pages, and a session in which they stayed at least 30 seconds, whether those were the same session or two distinct sessions.