Wash collard greens; dry. Fold greens in half with back side of stem exposed; cut out the stem using kitchen shears. Roll up the collard green; cut into small pieces.
Finely dice the tomatoes; be sure to keep the juice from the tomatoes. Finely chop the green onion.
Heat the olive oil over medium heat in a large saute pan until just hot. Add the collard greens. Cook over medium heat until greens just begin to cook down. Remove; place on a plate.
To the saute pan, add the tomatoes (with juice) and green onion. Cook until heated through but not mushy.
Crumble the salmon into bite-sized pieces. Add to the tomatoes. Add the collard greens back into the pan. Heat the combination until warmed throughout.
The salmon has a lot of taste by itself, so I don't add any other seasonings, especially not salt. This recipe can easily be increased by just doubling the amounts. If fresh tomatoes are not available, a can of chopped tomatoes will do.
A great way to get some greens into your diet. Of course, this is just as good without the salmon if you are vegetarian. In that case, I might add a few seasonings like garlic, salt, pepper, and basil.