Preheat oven to 425 degrees. Lightly grease a baking sheet with spray or additional olive oil.
Combine spices in a small bowl and mix together.
Combine chickpeas, tomatoes, parsley, olive oil and lemon in a large bowl. Add 1 teaspoon of the spice mixture to the bowl and toss to combine. Set aside.
Place the lamb loin in the center of the baking sheet. Rub remaining spice mixture all over the top of the lamb covering the top completely.
Scatter the tomato and chickpea mixture all around the lamb in an even layer.
Roast for 20-25 minutes depending on meat preference. Internal temperature should be about 145°F for medium-rare. Tomatoes will be wrinkled and starting to burst and chickpeas will be golden brown. Remove from oven, cover with aluminum foil and let rest for 5 minutes before slicing thinly.