How to Make It
In a medium skillet, toast the guajillo and chipotle chiles until lightly browned and fragrant, about 2 minutes. Transfer to a heatproof bowl and cover with boiling water. Let stand at room temperature until the chiles have softened, about 20 minutes.
Drain the chiles, reserving 1/4 cup of the soaking liquid. Stem and seed the chiles and transfer to a blender. Add the garlic, sesame seeds, clementines, honey, vinegar and the chiles' reserved soaking liquid and blend until smooth; season the salsa with salt.
In a medium bowl, mix the shallots with the jalapeño and 1/4 cup of the lime juice; season with salt. Let stand for 10 minutes. Whisk in the yogurt and mayonnaise, then fold in the crabmeat and season with salt and pepper. Refrigerate until ready to serve.
In a medium bowl, toss the cucumber with the remaining 21/2 tablespoons of lime juice and 1 teaspoon of salt. Let stand at room temperature for 10 minutes. Drain the cucumber and refrigerate.
Preheat the oven to 350° and position racks in the top, middle and bottom. Line 3 rimmed baking sheets with parchment paper and lightly grease. Mound four 1/4-cup portions of shredded cheese on each baking sheet; the mounds should be about 4 inches wide and 1 inch apart. Bake until melted and light golden brown, 12 to 14 minutes; shift the pans from front to back and top to bottom halfway through baking. Using a thin spatula, transfer the fricos to a rack and let cool completely.
Top each warm tortilla with a crispy frico. Spread some of the salsa on each taco and top with the crab, some of the cucumber, cilantro and sesame seeds. Serve with lime wedges and the remaining salsa and cucumbers.