In an oven-safe baking dish or directly on the rack, broil the poblano pepper and Fresno chile until skin is blackened, about 10 minutes, turning halfway through.
Place the peppers in a room-temperature bowl and cover with plastic wrap to steam for 15 minutes.
When cool, peel away the skin and remove the stem and seeds.
Chop finely and set aside.
Scoop the avocado into a bowl.
Coarsely mash it with a fork.
Stir in the onion, jalapeno, lime juice, salt, cilantro and roasted chiles.