2 whole-wheat burger buns, split and toasted
¼ cup crumbled feta cheese
½ tbsp. red-wine vinegar
¼ cup thinly sliced red onion
½ cup baby spinach leaves
2 garlic cloves, grated
¼ tsp. salt
½ tsp. crushed red pepper
2 tsp. chopped fresh oregano
1½ tbsp. extra-virgin olive oil
8 oz. ground turkey breast