Falafel Cheeseburgers with Tzatziki

I am a confirmed carnivore, but this recipe could almost make me vegetarian!  A nice change to a regular hamburger with lots of flavour.  Even the kids ate it (although I didn't tell them it was chickpeas)  From Food and Drink 2011

1 can (540ml) chickpeas, rinsed and drained
1/4 cup coarsely chopped fresh coriander leaves
3 tbsp olive oil
2 tbsp lemon juice
1 clove garlic, coarsely chopped
1 tsp ground coriander
1 tsp ground cumin
Generous pinch cayenne
Salt to taste
4 oz (125g) Halloumi cheese thinly sliced (or your favourite cheese)
4 burger buns
1/2 cup tzatziki
4 boston lettuce leaves
Sliced tomato, red onion and/or cucumber

1. Spread chickpeas out on a kitchen towel lined, rimmed baking sheet.  Blot with another towel until very dry.
2. In a food processor (I only have a blender so that is what I use), combine chickpeas, coriander leaves, 1 tbsp olive oil, lemon juice, garlic, coriander, cumin and cayenne.  Pulse until mixture forms a crumbly paste that holds together.  Taste and add a little salt and more cayenne if necessary.   Pulse again to combine.
3. Form mixture into 4 even sized patties, about 1/2 inch thick.  In a large nonstick skillet (I use my cast iron), heat remaining oil over medium heat.  Add burgers and cook for 3 to 4 minutes or until golden brown on the undersides.  Using an egg lifter, carefully turn burgers over.  Top each with halloumi.  Cook for 3 to 4 minutes or until burgers are golden brown and hot throughout, and cheese is starting to melt.
4. Meanwhile, split buns in half and toast until golden brown.  Spread bottom half of each bun with tzatziki.  Top with lettuce, and tomato, onion and/or cucumber.  Place a falafel burger on each bun.  Replace tops of buns and serve at once.