Shrimp Tacos with Avocado Sauce

First, prepare the Avocado Sauce: Add all sauce ingredients (2 pitted and diced avocados, ¼ cup Greek yogurt, ¼ cup fresh cilantro leaves, juice of 2-3 limes, kosher salt to taste, and a splash of water) to a food processor. Process until it forms a smooth, creamy consistency. 

Next, prepare the shrimp tacos: Heat the grill to medium-high. In a large bowl, mix the olive oil, 1⁄2 teaspoon chili powder, and 1⁄2 teaspoon kosher salt. Add the ten medium shrimp and toss to coat evenly. Grill the shrimp for about 2 minutes on each side, until cooked through. Grill the four whole wheat tortillas until slightly charred, about 20 seconds per side. 

To assemble the tacos, place the grilled shrimp, 1⁄2 chopped avocado, 1 Tbs. fresh cilantro, and pickled onions (if using) on each tortilla. Top generously with the prepared avocado sauce. Serve immediately with lime wedges.