Rinse green lentils under cold water. Combine with 3 cups of water in a saucepan and bring to a boil; then simmer for 20-25 minutes until tender. Drain excess water and set aside.

Heat olive oil in a skillet. Sauté chopped onion for about 5 minutes until translucent. Stir in minced garlic for an additional 1-2 minutes, then cool the mixture.

In a large bowl, mix cooked lentils, the onion and garlic mixture, panko breadcrumbs, beaten eggs (or flax eggs), chopped parsley, oregano, cumin, salt, and pepper until well combined.

Preheat oven to 375°F (190°C). Shape the mixture into golf ball-sized meatballs and place them on a greased baking sheet.

Bake meatballs for 25-30 minutes, until golden brown and fragrant.

For tzatziki, mix yogurt, grated cucumber, lemon juice, and salt in a bowl. Stir in dill if desired until smooth.

Serve the meatballs drizzled with tzatziki, alongside warm pita or a fresh salad.