Has this form of "kind-of-dual" homomorphisms been studied? Let $G_1=(V_1,E_1)$ and $G_2=(V_2,E_2)$ be graphs and let $h:V_2\to V_1$ be a map such that, for every edge $(u_1,v_1)\in E_1$, there is an edge $(u_2,v_2)\in E_2$ such that $h(u_2)=u_1$ and $h(v_2)=v_1$.

This kind of maps has occurred in our recent research in Database Theory. We think that it looks like a natural "dual" to graph homomorphisms, where $h$ would be $V_1\to V_2$ and map each edge of $G_1$ to an edge of $G_2$. However, we could not find it in the literature, but, since we do not have a name for it, maybe we searched in the wrong places.

Some background: in Database Theory, homomorphisms play an important role in the context of the containment problem for conjunctive queries. The "kind-of-dual" form occurs in the context of parallel query evaluation. 

In this slightly extended context, testing for existence of such a mapping is NP-complete, and I expect that also for graphs. However, I am not asking for complexity results, but I would be be grateful for pointers to the literature (or even a name, for that matter).
In the case of undirected graphs, there is literature about such morphisms called graph emulators.
They are a refinement of the notion of covering graph.
A covering graph maps the neighbourhood of a vertex $u$ bijectively to the neighbourhood of $h(u)$, while an emulator is only required to do it surjectively, which seems equivalent to your question.

This notion appears in the context of characterizing graphs having planar covers or planar emulators, which yields several open problems, see for instance this paper for a survey.