My dog area has only a couple tiny patches of green plants growing in it. Sometimes, Kobe will chew all of those down to the dirt at a time. I've read of the benefits of grass to a dog's gut.

What can I give him to fill this need he has? Is it fiber he's looking for?

I tried a few frozen green beans last night which he loved, but threw up shortly after. They had been in the freezer for ages. Maybe they were bad. He loves raw carrots, but the bag I had had turned to mush.

Canned or frozen vegetables? Something else?

Get some new frozen green beans, they are excellent treats.
It might work for dogs, I grow oat grass in planters inside for my cats to munch on.

I worked with my German Shepherd during training sessions with frozen green beans. He loved them more than dog treats! I just had a soggy pants pocket by the time we were done.

Would canned green beans straight out of the can be okay, or should they be raw? The frozen are raw, right?

In regard to soggy pants, Zip locs are your friend

I guess canned would be ok. In my opinion, all life is cooked out of canned veggies so I don't eat them. And I would not feed them to anything I loved...
Yes, frozen green beans are raw.

Your dog might like wheat grass. It is easy to grow, or you can buy trays of it at most health food stores. My dog would not eat it on its own, but I mixed it in to his regular dog food and he gobbled it down.

But perhaps you should talk with your vet regarding a good pre/probiotic for your dog. Do not give him yogurt or kefir as most dogs can't digest dairy.

No to canned green beans (for you or your dog) they have little nutritional value except some calories and some fiber. Empty calories are not worth eating, IMO.

Frozen green beans are okay for dogs. BTW they are NOT raw, they have been blanched. But that's a good thing, as raw green beans are hard for dogs to digest.