Grilled Skirt Steak with Blistered Tomatoes and Guacamole

Name: Grilled Skirt Steak with Blistered Tomatoes and Guacamole
Ingredients: 1 1/2 lb. skirt steak; 2 tsp. cumin; 1 tsp. coriander; 2 garlic cloves, minced; 4 tbsp. lime juice; 3 tbsp. extra-virgin olive oil, divided; 3 avocados, diced; 2 tbsp. finely chopped red onion; 2 tbsp. finely chopped fresh cilantro, plus cilantro leaves for serving; 1/2 tsp. crushed red pepper flakes; 3/4 c. red grape tomatoes, halved; 3/4 c. yellow grape tomatoes, halved; kosher salt; Freshly ground black pepper