Shish Kebab

Name: Shish Kebab
Ingredients: 1 3⁄4 lb. lamb shoulder, cut into 1″ cubes; 3 tbsp. extra-virgin olive oil; 1 tbsp. tomato paste; 1 tbsp. minced fresh thyme; 1⁄2 tsp. paprika; 1⁄4 tsp. cayenne pepper; 1⁄4 tsp. ground allspice; 1⁄4 tsp. ground cinnamon; 1⁄4 tsp. ground cumin; 3 cloves garlic, minced; Kosher salt and freshly ground black pepper, to taste; 1 medium yellow onion, thinly sliced; 1 tbsp. ground sumac; 24 cherry or grape tomatoes