Preheat a grill or grill pan over medium-high.
In a large bowl, toss the tomatillos and scallions with 1 tbsp. oil; season with salt and pepper. Grill until tender and lightly charred, 8 to 10 minutes; transfer to a cutting board and roughly chop.
In a medium bowl, mix the chipotles, garlic and the remaining 1 tbsp. oil; season. In another large bowl, toss half the chipotle mixture with the shrimp. Thread the shrimp onto skewers (soak wooden skewers in water 30 minutes before cooking) and grill until charred in spots and opaque in the center, 1 to 2 minutes per side. Slide the shrimp off the skewers and into the bowl with the remaining chipotle mixture; toss.
Grill the tortillas until charred in spots, 1 to 2 minutes per side.
In a small bowl, whisk the mayonnaise and hot sauce. Serve the shrimp with the tortillas, vegetables, spicy mayonnaise and lime.