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