In a small bowl, mix the flour with the salt and spices.
In a separate bowl, pour the buttermilk.
Slice the poblano peppers into 1/4" rings. Remove seeds and inner membranes (a spoon or a finger works well).
Stack tortillas and slice into 1/4" strips. Toss with 1 tbsp. of the seasoned flour and set aside.
Heat oil in a deep skillet or Dutch oven over medium-high heat (350°F -ish)
Working with just a few rings at a time, dredge each ring in seasoned flour, dip in the buttermilk, then dredge through the flour a second time.
Set aside on a rack or parchment-lined baking sheet to wait their turn in the frying oil.
Fry the flour-dusted tortilla strips in batches for 1-2 minutes -- don't overcrowd or they'll stick together. Turn a few times during frying until golden brown and crispy.
In the same oil, fry the poblano rings, a few at a time (don't overcrowd these either!) for 1-2 minutes, turning a few times, until golden brown and crisp all over.
Remove to drain on a paper towel-lined plate. Sprinkle with the crackle dust.