Add the rice wine vinegar, sumac, red chili flakes, coriander seed, peppercorns, bay leaf, brown sugar, and kosher salt to a saucepan. Bring the pickling liquid to a boil, then remove from the heat and stir in the ice to cool it down. Pour the chilled pickling liquid over the melon chunks and refrigerate for at least a few hours, or overnight for the best flavor.
Add the cumin seeds to a dry skillet over medium-high heat. Toast until deeply aromatic and very dark, just shy of burnt. Transfer to a mortar and pestle and crush, leaving some texture. Stir the toasted cumin into the labneh along with the olive oil, kosher salt, and black pepper. Mix until fully combined and set aside.
Slice the zucchini lengthwise and season with olive oil and kosher salt. Grill over high heat until deeply charred and tender. Transfer to a tray and allow the zucchini to cool slightly before cutting into bite-sized pieces.
Combine the grilled zucchini, pickled melon, dill, mint, olive oil, kosher salt, and black pepper in a large mixing bowl. Toss gently until evenly coated.
Pat the sea scallops completely dry with paper towels and season with kosher salt and black pepper.
Heat a heavy skillet over high heat. Sear the scallops until a deep golden crust forms on the first side, then flip and cook to your preferred doneness.
Add the butter to the pan. Once the butter begins to brown, add the lemon juice and spoon the brown butter over the scallops. Remove from the heat immediately.
Brush the pita breads with olive oil and season with za’atar. Warm in a skillet, on a grill, or in the oven until lightly toasted and fragrant. Cut into wedges.
Spread the burnt cumin labneh across a serving platter or individual plates. Spoon the grilled zucchini and pickled melon salad over the top, then arrange the scallops over the salad.
Serve immediately with warm za’atar pita and finish with a drizzle of extra virgin olive oil if desired.