Preheat the Oven: Set to 375°F (190°C).
Make the Meatballs: In a bowl, combine ground beef, ground lamb, breadcrumbs, red onion, garlic, beaten egg, oregano, cumin, salt, and pepper. Mix well. Shape into 1-inch meatballs.
Heat olive oil in a skillet over medium heat. Brown the meatballs on all sides. Cook in the oven for 10–12 minutes, to an internal temperature of 160°F (71°C).
Make the Arakas Latheros: Heat olive oil in a medium pot over medium heat. Sauté onion until soft. Add green peas and stir to coat with oil. Stir in water and tomato paste. Bring to a simmer covered with a lid. Cook until most of the water evaporates. Remove from the heat and stir in dill. Season with salt and black pepper.
Portion tomato and avocado slices. Drizzle with olive oil, sprinkle with garlic, oregano, and feta, and add a pinch of salt.
Mix the Drink: Stir together almond milk, cinnamon, and honey until well combined.
Serve the meatballs with ketchup, arakas latheros, tomato and avocado, Greek olives, and almond milk.