Preheat a grill to medium. Brush a baking sheet with 1 tablespoon olive oil. Turn the pizza dough in the oil to coat. Add the red onion rings to the baking sheet and turn to coat in the oil. Set aside until ready to grill.
Heat a large skillet over medium-high heat. Add the remaining 1 tablespoon olive oil and chorizo; cook, breaking up the meat with a wooden spoon, until it starts browning, about 2 minutes. Add the poblano and cook until it just begins to wilt and the chorizo is no longer pink, about 3 minutes. Add the corn and cook until tender, about 2 minutes. Season lightly with salt.
Arrange the onion rings on one corner of the grill. Grill, flipping, until lightly charred and crisp-tender, 8 to 10 minutes.
Meanwhile, stretch and press the pizza dough on the baking sheet into a 10-by-12-inch rectangle. Transfer the dough to the grill (it’s OK if it stretches slightly). Cook until golden and marked on the bottom, 3 to 4 minutes. Flip with tongs. Top with the salsa, jack cheese and chorizo mixture. Cover the grill and cook until golden on the bottom, 3 to 4 minutes.
Use a large spatula to slide the pizza onto a cutting board. Coarsely chop the onion rings and sprinkle on top of the pizza along with the queso fresco and cilantro. Cut into squares.