Place the seasoned salmon in a greased glass baking dish.
To prepare the grapefruit (2 only): With a sharp paring knife remove the skin by cutting first the ends and then the skin by cutting from top to bottom, removing all the white pith.
Then cut out each segment resulting in crescents with no membrane.
They should look like the mandarin orange segments that come in a can.
Squeeze the juice from the third grapefruit.
Scatter the leeks, grapefruit segments and mint over the salmon and add the juice.
Cover and bake at 400° for 20 minutes.