its rising rays spraying the forested hills

[alpacinoutd]

Is it correct to use "spray" like that? If not, what other verb can I use?

The sun was behind the towering mountain, its rising rays spraying the forested hills in an orange halo.

[tedmc]

The sun rises, not its rays.

How about lighting up/illuminating/bathing/infusing?

[alpacinoutd]

Fair enough. What about this?

The sun was behind the towering mountain, its hazy rays spraying the forested hills in an orange halo.

[Charlie Bernstein]

Halos are circular, so that's not an effective image.

And how much can the sun light the hills from behind a mountain? I can imagine it lighting the treetops.

As for style, your adjective-to-noun ratio is 4:5, which can get tiring quickly if you keep it up.

Here's a 1:5 ratio: From behind the mountain, the sun's orange glow lit the hills and trees.

Open up some contemporary English-language writers, and do some adjective-to-noun and adverb-to-verb counts.

[alpacinoutd]

Generally, can spray be used to talk about sunlight in any situation?

The sun was rising, its rays spraying the hills.

[Charlie Bernstein]

It's unusual, but there's nothing wrong with it

[tedmc]

I don't think it is a good idea to liken sunlight to the spray presumably from a liquid source, but it is subjective of course.