How to Make It
In a large bowl, whisk 8 cups of hot water with 1/2 cup of salt, the halved garlic head and the chopped dill sprigs until the salt is dissolved. Let cool to lukewarm.
Using a paring knife, pierce each piece of okra in a few spots to help absorb the brine. Add the okra to the brine and place a plate on top to keep them completely submerged. Let stand at room temperature for 2 hours.
Meanwhile, in a small bowl, combine the lebneh with the crushed coriander, grated garlic, chopped dill fronds and 1/4 cup of the olive oil. Add 2 tablespoons of water and season with salt and cracked pepper. Whisk until smooth.
Light a grill or heat a grill pan. Drain the okra and pat dry; discard the garlic and dill sprigs. In a medium bowl, toss the okra with the remaining 2 tablespoons of olive oil and season with pepper. Grill the okra over moderately high heat, turning, until charred in spots and crisp-tender, about 5 minutes. Spread the lebneh on plates and top with the blistered okra. Garnish with small dill sprigs and serve with lemon wedges.