Cook ham in a lightly greased skillet over medium-high heat 3 to 4 minutes on each side or until thoroughly heated. Remove ham, reserving drippings in skillet.
Stir in orange juice, and cook 2 minutes, stirring to loosen particles from bottom of skillet. Stir in pineapple, raisins, and mustard. Stir together cornstarch and 1 Tbsp. cold water; add to orange juice mixture. Bring to a boil; cook, stirring constantly, 1 minute. Serve sauce with ham.