Can impact craters on the moon act like giant radio telescopes?

Could large craters on the moon be used as reflective lenses for radio
signals?

You'd have to line the surface with something reflective to microwaves, like a metallic mesh, or similar materials.

Secondly, the shape of the crater is probably not quite ideal, so it would have to be adjusted a little, carved up a bit in various places. But it's a good start, and definitely better than starting with a flat ground.

There is also the question of stability - you need to make sure that whatever changes you make (carving a different shape, lining it with mesh) do not affect the stability of the crater, or else various parts may slide or collapse. This is an engineering problem.

Acting like a large radio telescope reflecting radio waves to a
satellite positioned over the crater.

Not possible unless the crater is exactly on the equator, and even then it would be tricky.

But a crater like the one in your picture is so strongly curved, the focal length is about the same as the diameter. In other words, if the diameter of the hole is X, the altitude of the receiver is pretty close to X - give or take something like 50% or so, depending on the exact curvature. It might be easier to just build a giant arch over the crater. Again, this is a matter of engineering.