In a medium mixing bowl, fluff up 1 tablespoon of lemon juice and 2 tablespoons of the olive oil until merge into one another and form a thick and smooth mixture.
Take two medium red onions and peel them properly, removing their out layer. Rinse the peeled red onion and cut them into fine slices. Now, take a medium bowl and place these onion wedges in it. Pour in 1 tablespoon of the recently prepared lemon dressing and toss the wedges gently to coat them evenly. Cover the bowl with wrapping sheet or flat plate and set the onion-dressing mixture aside to marinate for some time.
Top the remaining dressing with one very finely chopped garlic clove. Add in the delicately chopped sun-dried tomatoes long with the rinsed and drained pitted black olives. Mix up these ingredients until coat well in the dressing and set aside at room temperature to marinate thoroughly.
Note: The sun-dried tomatoes are easily available in the market; otherwise you can use the jar of preserved ones as well. However, make sure to drain them properly before adding them to the ingredients.
Grab a non-sticking ridged grill pan and set it on your stove with a medium heat range. Pour in the remaining olive oil and brush it all over the surface of ridged grill pan. Once the oil is warm, add in the coated onion wedges along with the mixture and cook for around 3 to 4 minutes on underside until properly browned. Now, take a flat wooden ladle or flat spatula and gently turn the mixture over. Now, add the thick slices of haloumi cheese into the pan. Increase the heat of your stove to medium-high and cook the onion mixture for 3 to 4 more minutes, and the haloumi cheese slices for 1½ minutes on each side or until tinged with brown.
Note: Continue the cooking of the haloumi cheese until it begins to melt at the edges. Secondly, you can replace the ridged grill pan with a sheet of foil under a medium grill in order to cook the onion- haloumi mixture.
At the same time as the onion- haloumi mixture is cooking, rinse the baby spinach leaves with a sieve or colander. Now, drain the spinach leaves thoroughly and place them on a large cutting board. Cut the woody stems and place them in a large serving dish or platter. Rinse and drain the fresh rocket leaves and arrange them at the top of spinach.
Remove the onion- haloumi mixture from heat and gently scoop it at the top of the rocket-spinach arrangement.
Place the hot grill pan back on the stove and reduce the heat to medium range. Gently tip the previously prepared tomato mixture onto it and cook it for few seconds until warm and steaming, stirring constantly.
Remove the fried tomato mixture from heat and drizzle it over the salad in the large bowl or platter.
Mix up the overall ingredients in order to coat them thoroughly.
Your Char Grilled Halloumi with Tomato and Olive Salad Dressing is all set; serve immediately and enjoy!
Note: You can serve the salad with some warm pita breads or seeded breads to improve its overall presentation and taste.