Prepare Corn Salad by combining the first 8 ingredients (corn, avocado, red onion, jalapeño, cilantro, lime juice, cumin, and paprika) in a large mixing bowl; toss to combine. Season to taste with kosher salt (I use ~1/2 teaspoon). Set aside.
Next, prepare Creamy Cilantro Sauce by combining all sauce ingredients (cilantro, yogurt, oil, mayo, lime juice, garlic, salt, and pepper) in a standard blender (you can also use an immersion blender). Blend until the sauce is smooth with bright green specks throughout.
Pat halloumi slices dry with a paper towel. Heat 1 to 2 Tbsp. cooking oil in a grill pan or cast iron skillet over medium-high. Once hot, arrange halloumi slices in a single layer and cook for about 2 minutes, until deeply golden. Flip and cook 2 more minutes. Transfer to a plate.
Assemble tacos by spreading a little Creamy Cilantro Sauce on each warmed tortilla. Add ~2 slices of halloumi cheese, followed by a big spoonful of corn salad. Drizzle extra sauce overtop, and garnish with extra cilantro, if desired.