Add meat to a bowl or tray and pat very dry with paper towel.
Divide mixture into 8 1/4lbs-portions and form into large meat balls. Season the top of each with kosher salt and black pepper.
Preheat a grill or cast-iron grill pan over med-high heat. When the pan is hot, raise the heat to high. Working in batches, add meat and use a large, metal, off-set spatula to smash the burgers down.
Baste each burger with a bit of the New Primal marinade and season with salt and pepper. Cook 3 minutes and flip. Baste the cooked side of the burgers with more marinade.
Flip once more and cook additional 30 seconds to caramelize the top coat of marinade.
Transfer cooked burgers to a tray. Add sliced pineapples to the grill pan, lower heat to med-high, and cook 3-4 minutes per side or until grill marks appear.
Assemble burgers on an iceberg lettuce bun. Top with grilled pineapple, chipotle mayo, diced onion and a drizzle of the marinade.