Preheat your oven to 400°F. Line a baking sheet with parchment paper.
In a large bowl, combine the ground meat, breadcrumbs, Parmesan cheese, parsley, onion, garlic, oregano, cumin, salt, pepper, and egg. Mix until well combined.
Form the mixture into small meatballs, about 1 inch in diameter, and place them on the prepared baking sheet.
Drizzle the meatballs with olive oil and bake in the preheated oven for 20-25 minutes, or until cooked through and browned.
While the meatballs are baking, prepare the tzatziki sauce. In a medium bowl, combine the Greek yogurt, grated cucumber, garlic, lemon juice, dill, salt, and pepper. Mix well and refrigerate until ready to serve.
Once the meatballs are done, remove them from the oven and let them cool slightly before serving with the tzatziki sauce.