Freeze extra chipotles in adobo individually in an ice cube tray.
Warm oil in a medium skillet over medium-high heat. Add corn, sprinkle with salt, and cook, stirring occasionally, until tender and beginning to turn golden, about 3 minutes. Add onion and poblano and cook, stirring, until corn starts to brown and onion and poblano soften, 2 to 3 minutes. Transfer to a medium bowl. (Alternatively, grill corn before removing kernels from ear. Slice onion and grill before dicing. Grill poblano, turning, until charred; remove skin and dice.)
When corn mixture has cooled, fold in tomatoes, chipotles, lime juice, and cilantro. Season with salt and pepper. Serve or cover and refrigerate for up to 1 day to allow flavors to develop.