Cook the whole fresh wax beans.
In saucepan combine sugar, vinegar, mustard, onion, salt, and 1/3 cup water.
Bring mixture to boiling, stirring till sugar dissolves.
Add drained cooked fresh beans or the drained canned beans.
Simmer, uncovered, for 5 minutes; cool.
Cover and refrigerate several hours or overnight, stirring occasionally.
Makes 2 cups relish.