To Make the Greek Tzatziki Sauce
Combine all Tzatziki Sauce ingredients in a medium glass bowl and refrigerate for at least an hour before use.
To Make the Greek Veggie Burger
Add the beans, onion, sun-dried tomato, and garlic to a food processor and pulse until the mixture has broken down and still clumpy; you don't want a smooth paste.
Transfer to a bowl and stir in the cooked rice, rolled oats, shredded carrots, egg, breadcrumbs, salt, pepper, cumin, oregano, and Worcestershire sauce. Mix well with your hands and form into 6 equal patties.
Heat the olive oil in a large skillet or cast iron pan on medium high heat. Put the flour on a plate and season it with a bit of salt and pepper.
Dip both sides of the patty into the flour before placing them in the hot skillet; brush off excess. Fry the patties for about 5 minutes on each side over medium heat, until each side is browned.
Remove the patties from the skillet and put on a bun bottom. Top them with red onion, Greek Tzatziki sauce, and bin t