1. Immerse tomatoes in boiling water for about 10 seconds; lift out. Pull off skins and cut out cores and discard. Cut tomatoes in half and squeeze juice into a 2- to 3-quart pan. Chop tomatoes into 1/4-inch pieces; add to pan, along with brown sugar, vinegar, and chilies.
2. Boil over high heat, stirring often, until tomatoes begin to fall apart and almost all the liquid has evaporated, about 5 minutes. Let cool. Add salt to taste. Serve, or cover and chill up to 2 weeks.
Nutritional analysis per 1/4 cup.