Bring salted water to a boil over high heat in a large pot. Add macaroni noodles and cook according to package instructions, adding in the peas in the last minute of cooking. Drain the macaroni and peas into a colander and rinse with cold water until cooled.
Add the roasted peppers, mayonnaise, crema, chipotle sauce, yellow mustard, salt and pepper to a blender. Blend until very smooth. Pour the mixture into a large bowl, set aside.
Heat a grill or grill pan to medium-high. Add the ham and corn to the grill and cook for 3-4 minutes, tossing and flipping occasionally, until the ham is browned on all sides and the corn starts to char. Remove the ham and corn from the grill. Chop the ham into 1/2-inch cubes and cut the corn from the cob. Transfer the corn and ham into the mayonnaise mixture. Add in the cooked macaroni and peas, along with the onion, celery, cheese and scallions. Toss everything together until coated. Serve immediately or cover and refrigerate until ready to serve.