Step 1Whisk 3 Tbsp. sugar, ¼ cup apple cider vinegar or red wine vinegar, and 1 Tbsp. Diamond Crystal or 1¾ tsp. Morton kosher salt in a small bowl until sugar and salt are mostly dissolved. Whisk in 1 Tbsp. onion powder, 2 tsp. garlic powder, 2 tsp. paprika, and 1 Tbsp. extra-virgin olive oil.
Step 2Pour marinade into a large resealable plastic bag. Add 1½ lb. skinless, boneless chicken thighs (about 6), close bag, and turn to coat. Let sit at room temperature 15 minutes, or chill, turning occasionally, up to 12 hours.
Step 3Meanwhile, heat 1 Tbsp. extra-virgin olive oil in a medium saucepan over medium-high. Add 1 cup Israeli couscous and cook, stirring to coat, until golden brown, 1–2 minutes. Carefully pour in 1¼ cups water and add ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt; stir well. Bring to a boil; immediately reduce heat to low and cover. Simmer until tender, 8–10 minutes. Remove lid, gently fluff, and let sit to allow excess moisture to evaporate.
Step 4Meanwhile, prepare grill for medium-high heat; oil grate with vegetable oil. Brush 2 medium ears of corn, shucked, with olive oil; grill, turning often, until tender and charred in spots, 7–9 minutes. Transfer to a cutting board and let cool. Cut kernels from corn cobs and place in a medium bowl.
Step 5Remove chicken from marinade, letting excess drip back into
bag. Grill, reducing heat or moving to a cooler spot if charring too quickly, until
cooked through and well browned, about 5 minutes per side. Transfer to cutting board and
let rest 10 minutes.
Step 6Add 12 oz. cherry tomatoes, halved, and Israeli couscous to corn and toss to combine. Drizzle in remaining 1 Tbsp. apple cider vinegar or red wine vinegar and 1 Tbsp. extra-virgin olive oil, season with salt and freshly ground pepper, and toss again. Transfer couscous salad to a platter. Finely grate zest from 1 lemon over, then cut lemon into wedges. Season salad with more pepper.
Step 7Slice chicken and arrange over salad. Top with basil leaves and serve with lemon wedges.
To make without a grill: Heat broiler. Place a wire rack inside a foil-lined rimmed baking sheet. Brush rack with vegetable oil. Place corn on rack; broil until tender and charred in spots, 8–10 minutes. Transfer to cutting board; let rest. Remove chicken from marinade, letting excess drip back into bag, and arrange, smoother side up, on same rack. Broil, turning once, until golden brown, 12–14 minutes.
