Heat a large skillet over medium heat and add the tablespoon of olive oil. Once hot, add the ground lamb or beef. Cook for 5-7 minutes, stirring occasionally until browned. Add garlic powder, onion powder, oregano, cumin, salt, and black pepper. Stir and cook for another 2-3 minutes. Remove from heat.

In a bowl, combine 1 cup of plain yogurt with 1/2 cup of grated cucumber, 1 minced garlic clove, 1 tablespoon of lemon juice, and a pinch of salt. Mix until smooth and creamy. Chill in the refrigerator.

Wash mixed greens thoroughly and place in a large bowl. Halve cherry tomatoes, dice cucumber, and thinly slice red onion. Add to the bowl with mixed greens. Crumble feta cheese on top.

Spoon the cooked meat over the bed of mixed greens and vegetables. Drizzle tzatziki sauce over the top. Serve with warm pita bread on the side.