Prepare a grill or grill pan for medium heat.

Whisk the zest and juice of 1 lime together in a small bowl with the crema and sriracha. Set the sauce aside.

Grill the corn, rotating the ears every few minutes, until all sides are charred, 10 to 12 minutes on a grill with the lid closed or 12 to 15 minutes on a grill pan. Set aside to cool slightly.

Oil the grill grates or pan. Grill the cheese until grill marks appear, 1 to 2 minutes per side. Set aside.

Grill the tortillas until just charred in spots, 1 to 2 minutes per side.

Cut the remaining 2 limes into wedges. Slice the corn kernels off the cobs.

To assemble the tacos, place 2 tortillas on a plate and top each with some corn kernels, 1 slice of halloumi, 2 to 3 slices of avocado, some radish slices and a sprinkle of scallions and cilantro. Finish with a drizzle of the sauce. Repeat with the remaining tortillas. Serve with lime wedges