Cook pasta in salted water until al dente, rinse under cold water to cool, then drain and set aside.
Grill jalapeños until soft and slightly charred. Let cool slightly, slice lengthwise (keep the seeds if you like it hotter) then cut across into smaller pieces.
Remove the husks and silk from the corn, wrap in cling film or place in a ziplock bag and microwave 5 minutes. Grill until nicely charred - let cool slightly, then cut off the kernels.
Mix dressing: combine the ranch, mayo, chipotle, lime juice, bacon fat, salt, and pepper - stir well.
In a large bowl, combine cooled pasta, bacon, jalapeños, corn, red onion and cilantro.
Add the dressing (I'd start with half) toss to coat evenly and top with the crispy onions just before serving.
