Combine all ingredients in a large bowl. Mix together well and form into 4 patties.
Grill until desired doneness.
Serve on regular hamburger buns or on pita bread with hummus.
Notes
This recipe is naturally gluten-free (as long as your olives and hummus are GF), but be sure to serve it without the bun (or with a GF bun) if you need it to be totally gluten-free.