[The Cajun]

The reason I say it looks more like a flow is because of the very low gravity on the small moon.
I think any ejecta dust/rocks from a large impact would have easily reach escape velocity and been on their way, where a molten flow might have stuck to the surface in spite of the nearly nonexistent gravity.

[SunkenCiv]

The lines look like the result of the lowest-velocity ejecta merely rolling across the surface; in any impact, some goes up and comes back down, some barely leaves the surface, some escapes.