In a large saucepan over medium heat, soften the onions for 5 minutes in the oil. Add the rice and broth. Bring to a boil. Cover and cook for 30 minutes over medium-low heat or until the rice is tender and all the liquid has been absorbed. Add the salmon cubes. Cook uncovered for 5 minutes, stirring frequently, until the salmon begins to flake. Season with salt and pepper. Set aside.
Meanwhile, in another large saucepan of salted boiling water, blanch the cabbage leaves for 5 minutes or until tender. Cool in an ice bath and drain. Pat dry with paper towels.
Lay the cabbage leaves flat and, using a paring knife, trim the thickest section of the stem at the base of each leaf.
Line a bowl with a 9-inch (23 cm) opening with 7 cabbage leaves, starting with the greenest leaves. Cover with one-third of the salmon mixture. Layer with 4 cabbage leaves. Cover with the remaining salmon mixture and the remaining 4 cabbage leaves. Press the stuffed cabbage into the bowl to create a rounded shape.
In a small bowl, combine the broth and tomato paste. Set aside.
Gently turn the stuffed cabbage out into a large skillet. Reshape, if needed. Pour the broth mixture into the skillet and place the cherry tomatoes around the cabbage. Season with salt and pepper. Bring to a boil. Cover and let simmer over low heat for 15 minutes or until the tomatoes burst and the cabbage is tender but still bright green.
Gently cut the stuffed cabbage into wedges and serve with the cherry tomato sauce.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.