Preheat the oven to 400 degrees F. Line a baking sheet with foil.
Add the tomatoes, corn, poblano, onions and garlic cloves to the prepared baking sheet. Toss with the canola oil and sprinkle with salt. Roast for 15 minutes. Remove the garlic, flip the poblano and corn over and continue roasting for another 15 minutes, until charred and the tomatoes have softened and begun to split. Let cool for at least 20 minutes.
Peel the garlic. Remove the skin and stem from the poblano (remove the seeds, too, for a milder salsa).
Add the roasted tomatoes, poblano, onions and garlic to a food processor, along with the cilantro, jalapeno, coriander, cumin, 2 tablespoons lime juice and 1/2 teaspoon salt. Process until the mixture is evenly combined but still has some texture (similar to crushed canned tomatoes). Remove to a bowl.
Cut the corn kernels from the cobs and stir into the salsa. Adjust the seasoning with salt and lime juice.
Serve at room temperature, or refrigerate until ready to serve (see Cook's Note). Garnish with cilantro leaves and serve with tortilla chips.
The salsa will get milder as it chills.