Parboil the potatoes: Add baby potatoes to a pot of salted water. Bring to a boil and cook 8–10 minutes until just fork-tender but not soft.
Drain and let steam-dry for a few minutes.
Make the marinade: In a bowl, combine harissa paste, olive oil, lemon zest, half the lemon juice, garlic, and honey (if using). Season with salt and pepper. Taste and adjust heat or acidity.
Prep the halloumi and veg: Pat the halloumi dry and cut into 1-inch cubes.
Trim asparagus and cut into 2-inch pieces. If any potato halves are large, cut them to roughly match the size of the halloumi for even grilling.
Toss to coat: In a large bowl, gently toss potatoes, halloumi, and asparagus with the marinade until evenly coated. Let sit for 10–15 minutes while you preheat the grill.
Preheat your cooking surface: Heat a grill or grill pan to medium-high.
If broiling, set the oven rack about 6 inches from the heat and preheat the broiler. Lightly oil grates or pan.
Skewer the ingredients: Thread potato, halloumi, and asparagus onto skewers, alternating for color and texture. Don’t pack too tight—space allows better browning.
Grill or broil: Cook for 8–12 minutes total, turning every few minutes until the halloumi is golden and the potatoes and asparagus have charred spots.
If broiling, flip halfway.
Finish with lemon and herbs: Transfer to a platter. Squeeze the remaining lemon juice over the top and shower with chopped herbs. Add a pinch of salt if needed.
Optional sauce: Stir lemon juice, a spoon of yogurt or tahini, a drizzle of olive oil, and a pinch of salt into a quick sauce.
Serve alongside for dipping.