From ham steak, remove rind and trim off all but 1/4-inch of outer fat. Cut ham into 4 serving pieces.
In a large saute pan set over moderately high heat, melt 2 tablespoons of butter. Add ham steaks and saute for 3 minutes on each side, until steaks are lightly browned. Transfer ham steaks to plate.
Blot the pineapples as dry as possible. Add remaining 2 tablespoons of butter to saucepan. Add pineapple and saute until the edges begin to caramelize, about 4 to 5 minutes. Remove the pineapple and reserve. Add orange and pineapple juices to the pan and reduce by 1/2, for about 5 to 6 minutes. Whisk in Dijon and whole-grain mustards. Transfer ham steaks back into saute pan. Add caramelized pineapple chunks and toss. Heat through thoroughly. Season, to taste.