Preheat grill or grill pan over medium high heat.
In a small bowl, combine bread and milk. Let stand 5 minutes until bread absorbs milk.
In a large mixing bowl, combine ground beef, bread mixture, water chestnuts, teriyaki sauce, egg, ginger, garlic, and onion. Mix until combined. Divide the meat into quarters and form each portion into a patty.
Grill each patty 5 to 7 minutes on each side, until meat thermometer reads 165 F when the probe is placed in the center of the patty. If desired, grill pineapple on grill 2 to 3 minutes per side.
Place grilled burger on toasted hamburger bun and top with pineapple ring. Serves 4.