Using a paper towel, pat your chicken very dry all over and set it on a wire rack set over a rimmed baking sheet.
In a food processor or blender, combine the remaining ingredients for the tandoori chicken and pulse until the mixture is smooth and well-combined. Spread the mixture all over the chicken (on both sides) until it's completely coated. Place in the refrigerator (on the baking sheet) uncovered for 4-8 hours.
Preheat an oven to 425 degrees F. Remove the chicken from the fridge and place it in the oven. Roast for 50 minutes or until a thermometer inserted into the thickest part of the thigh registers 165 degrees F on a probe thermometer. Allow the chicken to rest for 10 minutes before cutting up and serving.
To make the raita: combine all the ingredients in a small bowl and stir until well combined. Store in an airtight container in the fridge until ready to use.