Cut the chicken breast into bite-sized pieces. Season them with a pinch of salt, black pepper, and garlic powder.
Cut the cherry tomatoes in half. Slice the cucumber into half-moons and the red onion into thin lengths.
For the avocado mousse, scoop the flesh of the avocado into a bowl. Mash it well with a fork. Season with a pinch of salt, black pepper, garlic powder, chili flakes, and a squeeze of lemon juice. Mix until smooth.