Trim excess fat from 1 pound fully cooked boneless ham; slice into 4 portions.
Blend 1/3 cup pineapple juice; 2 tablespoons soy sauce; 3/4 teaspoon ground ginger; and 1/2 clove garlic, minced.
Pour over ham in shallow container.
Marinate 30 minutes, turning once.
Remove ham from marinade; reserve marinade.
Grill over hot coals till heated through, about 2 minutes on each side.
Brush often with reserved marinade.
Heat 4 canned pineapple slices (juice pack) on grill during last 2 minutes.
Serve pineapple atop ham