Adjust rack to top position (top and middle positions for 4 servings) and preheat oven to 450 degrees. Wash and dry produce.

Cut potatoes into ½-inch-thick wedges. Halve, peel, and thinly slice onion. Halve, core, and thinly slice bell pepper into strips. Roughly chop cilantro leaves and stems. Trim and thinly slice scallions. 

In a large bowl, toss together potatoes, onion, bell pepper, tomato paste, five-spice powder, and a pinch of salt until veggies are well coated.

Spread veggies out in an even layer on a parchment-lined baking sheet (divide between two baking sheets for 4 servings). Reserve bowl. 

Roast on top rack (top and middle racks for 4) until tender and lightly browned, 20-25 minutes.

Meanwhile, in bowl used for veggies, combine tempura batter mix, ⅓ cup cold water, and ½ tsp salt (⅔ cup cold water and 1 tsp salt for 4 servings).

Pat chicken* dry with paper towels; season all over with salt and pepper. Slice crosswise into 1-inch strips.

Stir chicken strips into batter until evenly coated.

Heat a ¼-inch layer of oil in a large, preferably heavy-bottomed, pan over medium-high heat. Once oil is hot enough that a drop of batter sizzles when added to the pan, add coated chicken in a single layer, shaking off any excess batter (work in batches if necessary). Cook until golden brown and cooked through, 3-4 minutes per side. TIP: To check for doneness, cut one strip in half.

Using tongs or a slotted spoon, transfer to a paper-towel-lined plate.

In a medium microwave-safe bowl, whisk together Szechuan paste, curry paste, and 1 TBSP water (2 TBSP for 4 servings). Tightly cover with plastic wrap.

Microwave until sauce is warmed through, 30-45 seconds.

Transfer crispy chicken to baking sheet with roasted veggies. Add half the cilantro and half the scallions; toss to combine.