Spanakopita Turkey Burgers

Name: Spanakopita Turkey Burgers
Ingredients: 2 teaspoons extra virgin olive oil; 1/2 small red onion, chopped; 2 cloves garlic, minced; salt and pepper; 1 box frozen spinach, thawed & squeezed dry of excess moisture; 1 teaspoon dried oregano; 1 Tablespoon grill seasoning; 4 oz crumbled feta cheese; 1 1/3 pounds 99% lean ground turkey breast; 1 clove garlic; 1/3 seedless cucumber, grated & squeezed dry of excess moisture; 6 oz plain Greek yogurt; 1/2 teaspoon dried oregano; 1/2 lemon, juiced; 4 buns; Red onion, sliced; 2 tomatoes, sliced; 1/4 cup pitted kalamata olives, sliced in half