To build the skewers, place a shrimp on the skewer, followed by onion and pineapple. Now add another shrimp and continue the pattern until you have 4 shrimp, 4 onion chunks and 4 pineapple pieces on each skewer, or until you fill up the skewer.
Season the medallions and skewers with salt and pepper. Brush a little teriyaki sauce onto the shrimp.
Now place on grill. Cook the medallions for about 3-5 minutes per-side for medium rare. Cook the skewers for about 2 minutes per-side. Baste the shrimp regularly with the teriyaki sauce while cooking until done.
Remove the medallions and skewers from the grill. Let the meat rest and enjoy with a green salad.