Bring a pan of water to a boil, add the pasta and return to a boil. Boil about 10 minutes until just tender. Drain well, then return the pasta to the hot pan.
Meanwhile, put the cream cheese and milk into a small pan and heat gently, stirring until the cream cheese melts. Add the tomatoes and stir about 1 minute, then stir in the smoked salmon and chives. Pour the sauce over the drained pasta and stir together. Serve hot.