Preheat an outdoor grill for medium-high heat and lightly oil the grate.
Place poblano peppers, corn, onion, carrot, and garlic on the preheated grill. Roast for 2 to 3 minutes and remove garlic and onion. Continue roasting poblano pepper, corn, and carrot until you get a nice, even char, 3 to 4 minutes more.
Place blackened peppers into a bowl and cover tightly with plastic wrap. Allow peppers to steam as they cool, about 20 minutes. Remove and discard skins and seeds.
Cut kernels off of corn cob. Dice onions, carrots, and poblanos into medium-sized pieces. Mix garlic and 1 pinch salt together in a bowl to make a paste.
Whisk cilantro, olive oil, lime juice, and garlic paste together in a medium bowl. Mix in roasted vegetables. Season with salt and pepper. Refrigerate until ready to serve, at least 30 minutes; serve chilled.