Just like https://meta.stackexchange.com/q/148977/295232, it's currently only possible with a [SEDE query](https://data.stackexchange.com/stackoverflow/query/1030184/all-questions-with-exactly-two-specified-tags?tag1=c%23&tag2=winforms).

[<img src="https://i.sstatic.net/AMy3g.png" width="400" />][1]

But since there are many tags which don't have any influence on your ability to answer the question, it's probably better to focus on a few tags which you want to exclude, e.g.

    [c#] [winforms] -[linq] -[sql]

([results](https://stackoverflow.com/search?q=is%3Aq+%5Bc%23%5D+%5Bwinforms%5D+-%5Blinq%5D+-%5Bsql%5D&mixed=1))


  [1]: https://i.sstatic.net/AMy3g.png