Spanakopita Chicken Meatballs with Spicy Cucumber and Yogurt Sauce

Name: Spanakopita Chicken Meatballs with Spicy Cucumber and Yogurt Sauce
Ingredients: 1 tablespoon extra-virgin olive oil, plus some for liberal drizzling; 1 small onion, finely chopped; 4 cloves garlic, chopped, divided; 2 boxes frozen chopped spinach, defrosted.; 3/4 cup crumbled feta cheese; 1 pound ground chicken; 1 tablespoons grill seasoning (recommended: McCormick Montreal Seasoning); 1 1/2 cups Greek style plain yogurt; 1/3 seedless cucumber, peeled and chopped; 3 tablespoons fresh dill; 1/2 lemon, juiced; 1 1/2 teaspoons, 1/2 a palm full, cumin; 1 1/2 teaspoons, 1/2 a palm full, coriander; Salt