In a bowl, combine all of the meatball ingredients, and using your hands, work the meat mixture together until everything is well combined.
Using your hands, roll meat mixture into balls, approximately golf ball size. I used an ice cream scoop to ensure my meatballs were uniform in size.
Transfer meatballs to a large baking sheet, continuing to roll meat mixture until all has been formed into balls.
Transfer baking sheet to the oven for 25 minutes until meatballs are all cooked through.
Optional: Once the meatballs are cooked, you can remove them from the baking sheet and very quickly fry them in a cast iron skillet to crisp the exterior up a little bit.
While the meatballs are cooking, prepare the tzatziki sauce. Slice the cucumber lengthwise, remove the inner seeds, and use a cheese grater to grate the cucumber into small pieces.
Combine the Greek-style yoghurt, shredded cucumber, mint, garlic, olive oil, lemon juice and sea salt in a small bowl and stir to combine.