Is there way to control opacity of selection/active color in 3DView? In the user preferences, color for selection and active object can be set, but there is no alpha slider, i.e. opacity is always 100%.

I want to match a slightly distorted texture onto an object using UV editing, but due to the selection mesh lines showing in the 3DView with 100% opacity, it is hard to do this with pixel accuracy.

It there a way to set opacity of the selected mesh (by default: orange) or an alternative solution for this use case?
No, this feature isn't currently available. Workarounds can be found in following questions: Remove selection overlays when Editing UVs?