Combine beef with onion, parsley, garlic, Worcestershire; form 8-12 small patties.
Heat griddle over medium-high heat. Spray with cooking spray and grill burgers a couple of minutes on each side. Top burgers with 2 squares of cheese per patty, melt under foil tent in last minute or so, remove from heat.
Combine lettuce, tomatoes and onions on a platter; arrange burgers over top.
Whisk up mustard, ketchup, relish, vinegar and oil. Pour dressing over salad, garnish with pickle chips and serve.