Prep everything first: dice the avocado and tomatoes, mince the onion and garlic, squeeze the lime, and pick through the shredded chicken to remove any large clumps. Prepping mise en place keeps assembly fast and ensures the avocado is added at the last moment so it stays bright and doesn't brown.

Make the avocado salsa: in a medium bowl gently toss the diced avocado with the diced tomatoes, 1/4 of the minced red onion, 1 teaspoon of lime juice, 1 teaspoon olive oil, half the chopped cilantro, a pinch of salt and a few grinds of black pepper. Use a light hand when tossing so the avocado keeps some texture—this gives a creamy contrast to the warm, seasoned chicken.

Warm and season the chicken: heat 1 tablespoon olive oil in a large skillet over medium-high heat until shimmering (this temperature lets spices bloom and the chicken warm quickly without drying). Add the remaining minced red onion and the optional garlic and cook 30–45 seconds until fragrant—toasting the aromatics releases sweetness and builds flavor.

Add the shredded chicken and spices: add the 400 g shredded chicken to the skillet and sprinkle over 1 teaspoon ground cumin, 1 teaspoon chili powder, 1/2 teaspoon salt (or to taste) and 1/4 teaspoon black pepper. Sear the chicken for 2–3 minutes, stirring frequently, until the chicken is hot and the spices are fragrant. Heating the chicken in the skillet allows the spices to 'bloom' in fat so their aroma and depth intensify.

Finish the chicken for brightness: squeeze the remaining 1/2 lime juice over the chicken, toss in the remaining cilantro, and taste—adjust salt, pepper or a pinch more chili powder if you want extra heat. The acid brightens the spices and rounds the dish.

Prepare the lettuce cups: separate and rinse lettuce leaves, then pat completely dry with clean towels. Dry leaves hold fillings better and won’t become soggy. If using romaine, trim the ribs so the leaves sit flat; butter lettuce may be used whole as small bowls.

Assemble the wraps: spoon a generous 100 g portion of warm chicken into each lettuce leaf (about 2 leaves per serving if you want two small wraps), top with 2–3 tablespoons of the avocado salsa, and finish with a sprinkle of extra cilantro and a crack of black pepper. Assemble at the last minute so the avocado stays fresh and the lettuce is crisp.

Serve and enjoy: arrange wraps on a platter and serve immediately. These hold for a short time (20–30 minutes) assembled; for make-ahead, store chicken and avocado salsa separately and assemble just before serving to preserve texture.