In a medium bowl, combine red wine vinegar, sugar, garlic, salt and pepper. Add the chopped cucumber and scallions. Mix well and set aside while you prepare the other ingredients.
Combine quinoa with 2 cups of water in a saucepan. Bring to a boil, lower the heat, cover and cook till the quinoa is cooked through and tender. Turn off the heat and set aside for 5 minutes. Fluff quinoa with a fork and let cool.
In a large bowl, whisk oil and 1tbsp lemon juice. Add cooked quinoa, parsley, mint and chopped lettuce. Toss to evenly coat all the ingredients with the dressing.
Heat the grill over medium heat and grill halloumi until golden, about 1~2 minutes per side. Squeeze a little lemon juice on the cheese when done.
Divide the salad between 4 serving plates, top each with 2 slices of halloumi and the marinated cucumbers without the liquid. Enjoy!!