Vegan Chipotle Lentil Tacos

Name: Vegan Chipotle Lentil Tacos
Ingredients: 2 1/2 c. cooked green lentils (from about 1 cup dried); 1 tbsp. extra-virgin olive oil; 1/2 yellow onion, finely chopped; 2 garlic cloves, minced; 3 tbsp. tomato paste; 1 chipotle pepper in adobo sauce; 1 tsp. ground cumin; 1/2 tsp. ground coriander; Kosher salt; 1/2 avocado; Juice of 1 lime; 1/4 c. fresh cilantro leaves and tender stems; 1 garlic clove, minced; 1/2 tsp. kosher salt; 8 corn tortillas, warmed; Pickled red onions; Cilantro leaves, for serving