On desktop (with keyboard shortcuts) you can now mark card as failed ("No" answer), without flipping the card first.

(...) sometimes I remember the primitives (or "idea" of the primitive) and the overall story of a kanji, but don't actually remember how to draw a particular primitive itself. In these cases I want to mark the card as failed, but I don't want to see the kanji (...)

Thanks to Betadel for the suggestion (Github issue #163).