Preheat the grill to medium-high heat.
In a bowl, combine shrimp, chili powder, cumin, salt, and pepper. Toss to coat evenly.
In a separate bowl, mix together cabbage, cilantro, lime juice, and honey to make the slaw.
Place the shrimp on the grill and cook for 2-3 minutes on each side until opaque and cooked through.
While the shrimp cook, warm the corn tortillas on the grill for about 30 seconds per side.
Assemble the tacos by placing grilled shrimp in each tortilla, topping with cilantro lime slaw, and slices of avocado if desired.
Serve immediately with extra lime wedges on the side.