Pat dry and season: Pat the chicken dry with paper towels. In a small bowl, mix salt, pepper, smoked paprika, garlic powder, onion powder, cumin, and cayenne.
Toss chicken with olive oil and the spice mix until evenly coated. Let it rest 15–30 minutes at room temperature.
Make the pineapple BBQ glaze: In a saucepan, combine pineapple juice, ketchup, apple cider vinegar, brown sugar or honey, soy sauce, Dijon, garlic, and ginger. Bring to a simmer over medium heat and cook 6–8 minutes, stirring occasionally, until slightly reduced.
If you prefer a thicker glaze, whisk in the cornstarch slurry and simmer 1–2 more minutes. Taste and adjust salt, sweetness, or tang.
Choose your cooking method: Preheat a grill to medium-high heat (375–425°F), or set your oven to 425°F with a rack in the upper third. You can also use a stovetop grill pan or cast-iron skillet over medium-high.
Grill method: Oil the grates.
Grill chicken 5–6 minutes per side, depending on thickness. During the last 2–3 minutes, brush on glaze and flip once more to lightly caramelize. Grill pineapple rings for 1–2 minutes per side until charred.
Oven method: Place chicken on a foil-lined sheet pan with a wire rack if you have one.
Bake 12–15 minutes, brush with glaze, then broil 2–3 minutes to caramelize. Add pineapple pieces to the pan for the last few minutes if using.
Stovetop method: Sear chicken 4–5 minutes per side in a hot, lightly oiled skillet. Reduce heat, brush with glaze, and cook 1–2 more minutes until sticky and cooked through.
Check doneness: Use an instant-read thermometer. Chicken is done at 165°F in the thickest part.
Remove from heat and rest 5 minutes.
Serve: Slice or leave whole. Spoon extra warm glaze over the top. Garnish with cilantro or green onions and serve with lime wedges and grilled pineapple.