Tandoori Coconut Chicken

Name: Tandoori Coconut Chicken
Ingredients: For the marinade and chicken:; 1/4 cup white vinegar; two 14-ounce cans unsweetened coconut milk; one piece 3-inch by 1-inch fresh ginger, peeled and julienned; 1 clove garlic, crushed; 4 pounds bone-in, skinless chicken thighs; For the spice paste:; 2 tablespoons cumin seeds; 1/2 teaspoon cardamom seeds (from about 12 to 15 pods); 1/2 teaspoon whole cloves; 3 teaspoons coriander seeds; 2 bay leaves; 2 teaspoons kosher salt; 1/2 teaspoon black peppercorns; 1 teaspoon sweet paprika; 2 teaspoons annatto powder; 3 teaspoons ground turmeric; 1/2 teaspoon ground cinnamon; 2 fresh lemons, zest and juice reserved; 1 cup coconut oil, warm and melted; 1 red onion, sliced for garnish (optional); 2 lemons, washed and thinly sliced for garnish (optional