In large bowl, mix first 4 ingredients with 1 tsp. salt and 1/2 tsp. pepper; shape into 8 oval patties. In ovenproof skillet, cook over medium-high, flipping once, 5 minutes. Bake at 450 degrees until cooked, 8 minutes. In bowl, mix next 3 ingredients. Serve beef in lettuce leaves, drizzled with yogurt and sriracha.