Drain the salmon and reserve the juice from the tin. Remove any skin and bones from the salmon and seperate the fish into large flakes.
In another bowl, combine the salmon juice and the lemon juice.
Spread 1/4 of the cooked rice into the base of a greased casserole dish. Add 1/3 of the salmon and sprinkle over some of the lemon juice mixture. Next add a layer of tomatoes, sprinkle with salt and pepper and some of the shallots.
Add two more layers of the rice, salmon. tomatoes and shallots. Finish with a layer of rice.
Pour the melted butter over the final rice layer and sprinkle with the cheese.
Bake uncovered for about 30 minutes- should be very hot all the way through. Stand 5 minutes before serving.