Greek Chicken Burgers with Tzatziki

Name: Greek Chicken Burgers with Tzatziki
Ingredients: 1 pound ground lean chicken; 1 teaspoon lemon juice; ½ teaspoon oregano; ½ teaspoon basil; 2 green onions, chopped; 1 clove garlic, minced; 1 tablespoon kalamata olives; 1 teaspoon brine from olives; ¼ cup feta cheese, crumbled; Pinch of black pepper; Romaine lettuce; 1 tomato, sliced; 4 large mushrooms, sliced (optional); Pepperocinis, sliced (optional); 4 whole wheat hamburger buns; 1 cucumber, peeled; 1 cup 0% plain yogurt or greek yogurt; Salt and pepper to taste