First prepare a baking sheet or other flat surface with some parchment paper. Toast the walnut pieces in a dry skillet/frying pan for a couple minutes until they are starting to smell slightly toasted and are gently browning - turn part way, and take care they don't burn. Drizzle over the ½ tablespoon maple syrup and toss the nuts with a plastic spatula so they become coated. Remove from heat.
Tip the walnuts on to the parchment and spread out so they are separated then leave to cool. If any are slightly stuck, they will separate best once fully cooled. The nuts can be made a week or two ahead and stored in an airtight container.
To make salad
Cut the halloumi into slices and halve the slices if large. Fry on both sides in a dry skillet/frying pan until golden on both sides, a couple minutes each side.
Place the arugula/rocket in the bottom of your serving plate(s). Dice the cucumber and halve the tomatoes and scatter over the top. Then top with around half of the pomegranate and walnuts. Add the slices of halloumi then top with the rest of the pomegranate and walnuts.
Whisk together the olive oil, pomegranate molasses, lemon juice, Dijon mustard and honey (plus a little black pepper, if you like) and drizzle over the top.