Heat your grill - I use a simple grill skillet for quicker results in my kitchen, but any grill will do.
Use a fork to mash the avocado into a medium bowl, add 1 tsp lemon juice, mix to combine and set aside.
Add the lemon juice, mustard, olive oil and salt into a small jar, lid and shake well to get a creamy dressing.
Add the halloumi slices and bell peppers on the grill. Cook the halloumi for 3 minutes, then flip over and cook for 3 more minutes. Grill the red peppers turning them on each side, until well cooked (about 15 minutes)
Remove the halloumi from the grill and place into a bowl.
Remove the bell peppers from the grill, peel their skins, cut into stripes and remove the seeds and stems. Place in a bowl, drizzle with vinegar and set aside.
Keep the grill hot over low heat until the wraps are ready.
To assemble the wraps, start by spreading half of the avocado mash onto a tortilla, leaving 1 inch round from the side.
Add a few spinach leaves and top with a few drops of dressing.
Add half of the pepper slices, well drained of the vinegar, and cover with more spinach leaves.
Top with the half of the halloumi slices, red onion and crushed walnuts.
Add a few more drops of dressing and roll into a wrap.
Place on the grill and cook for 2 minutes on each side.
Remove from the grill, cut into halves and serve warm.
If you don't want to serve them right away, skip the dressing and wrap in plastic foil. Keep in the refrigerator and grill later. Keeps up to two days.