Finely grate orange and lemon peels; squeeze and reserve juices.
In a large saucepan, combine peels, juices, sugar, rhubarb, strawberries and salt.
Cook and stir over medium heat until sugar dissolves; add raisins.
Bring to a full rolling boil; cook over medium heat until thick, about 5-10 minutes.
Pour hot jam into hot jars, leaving 1/4-in.headspace.
Process for 10 minutes in a boiling-water bath.