Bring 1½ quarts of water to a boil with the salt and a little olive oil.
When water boils add the orzo a little at a time to keep the water boiling.
Cook the orzo about 10 minutes, or until not quite done.
Drain the orzo.
In a saucepan, brown the onions in 1 tablespoon olive oil until golden, then add the chopped tomatoes, teaspoon salt and all the thickened liquid from the lamb. Stir and bring to a strong simmer. Add the orzo and simmer, covered, for 10 minutes.
Serve with the lamb.