To cook the lamb: Heat the olive oil (2 tablespoons) in a nonstick skillet and cook the yellow onion over medium-high heat until softened and beginning to brown (about 2 minutes). Add the minced garlic and chopped oregano (2 tablespoons) and sauté until fragrant (about 30 seconds). Add the lamb and cook completely, breaking it up as you go (about 5 minutes). Season with ½ teaspoon of kosher salt and ¼ teaspoon of black pepper.

To make the Tzatziki Sauce: Squeeze as much water out of the grated cucumber as possible using a clean kitchen towel (see notes). In a small bowl, mix together the Greek yogurt (1 cup), ¼ teaspoon kosher salt, 1 tablespoon olive oil, 1 minced small clove of garlic, fresh chopped dil (1 tablespoon)l, and lemon juice (1 tablespoon). Add the cucumbers and stir.

To assemble the tacos: Spread ¼ cup of the tzatziki sauce on each tortilla, followed by ¼ of the lamb mixture, and the diced cucumber, fresh tomatoes, and red onion divided evenly. Finish with 1 oz. of crumbled feta on each taco.

Serve immediately, wrapped in foil or held together with a toothpick if desired.