Roasting a poblano pepper: preheat your oven to 450 degrees F (230 C).

Cut your poblano pepper down the center into two halves and remove the stem and all the seeds. 

Place your pepper halves face down on an aluminum foil-lined sheet pan. 

Bake for 20 to 25 minutes or until the skin of the pepper is turning fairly black. 

Remove your pepper halves from the oven and transfer into a bowl large enough to hold them. At this point you want to steam them slightly to make the skins easier to remove. You can either cover your bowl with another inverted bowl or you can cover your bowl with something like plastic wrap. Covering a bowl with a cutting board will also work. You're just trying to trap the stem in with the roasted pepper halves. 

After about 5 or 10 minutes, your pepper should be cool enough to handle. 

Remove from the bowl to a cutting board and carefully strip off all the skins and the burned or charred bits of pepper skin or flesh. Discard all the burned parts and the skin. 

Slice your roasted peppers into slices and then slice the slices into a small dice. Place the diced poblano in a large bowl.

Cooking corn kernels: clean eight ears of corn and slice the kernels from the cob. Add a teaspoon of olive oil to a large pan over medium heat and when the oil is shimmering, add the corn kernels. Cook, stirring often until the corn is just starting to soften and brown in some spots. This should take about 10 or 15 minutes. 

Add the cooked corn kernels to the large bowl with the diced poblano to cool.

Corn salsa assembly: finely dice half of a large red onion and a jalapeno pepper and add them both to the bowl with the corn and poblano. 

Add lime juice, cilantro, cumin, and salt to the bowl with the corn and all other veggies. Stir together well and then store in a sealed container in the fridge for up to a week. 

Chicken grilling: preheat a gas or charcoal grill for 10 minutes (or grill pan on your stovetop). 

Season the chicken on both sides with salt and pepper (or your favorite grill seasoning) and then cook the chicken pieces on grill grates for 4 to 5 minutes per side for thighs and 5 to 6 minutes per side for chicken breasts. If you have very large chicken breasts you might want to grill for 7 minutes. If you have a probe thermometer you should be looking for 165 degrees F (73 C). You should be able to pull the chicken off the grill 5 degrees less than your target temperature and it will carry over cook those extra degrees. 

Allow the chicken to cool for about 5 minutes and then slice into sandwich-sized slices. 

Sandwich assembly: lightly toast a sandwich roll. Spread jalapeno mayonnaise on the bottom roll and then top that with some scoops of corn salsa. Add sliced, grilled chicken. 

Layer on a few pickled red onions and top those with crumbles of cotija cheese. Add more jalapeno mayonnaise to the top of the roll if desired, close the sandwich and serve.