In a large mixing bowl, combine ground beef, minced garlic, finely chopped onions, breadcrumbs, baking soda, and fresh herbs. Drizzle in olive oil and season with salt and black pepper. Mix just until combined, cover with plastic wrap, and refrigerate for at least 2 hours.

Preheat your oven to 425°F (220°C). Roll the meatball mixture into uniform balls, about 1-1.5 inches in diameter, and place them on a greased baking sheet. Bake for approximately 30-40 minutes until browned and cooked through.

Cut potatoes into wedges, toss with olive oil and seasonings, then spread on a separate baking sheet. Roast for 40-60 minutes, flipping halfway through until golden and crispy.

In a medium bowl, combine thick Greek yogurt, grated cucumber, minced garlic, lemon juice, and chopped dill or mint. Stir well and season with salt. Cover and chill until ready to serve.

Layer lettuce at the bottom of the bowl, add roasted potatoes, then meatballs. Top with fresh tomatoes, cucumbers, red onions, and a good dollop of tzatziki sauce. Garnish with kalamata olives and additional herbs.