1. Mash garlic and 1/2 tsp. salt on a cutting board with the back of a fork until a paste forms. Transfer to a medium bowl and whisk in lemon juice, cumin, paprika, and pepper.
2. Add chicken and stir to coat.
3. Heat oil in a cast-iron skillet over medium-high heat. Add onion and cook, stirring occasionally, until golden brown, 6 to 8 minutes.
4. Using a slotted spoon, transfer the chicken to the pan (reserve the marinade) and cook, stirring occasionally, until opaque on the outside, about 4 minutes.
5. Add tomatoes with thier juice, chickpeas, the reserved marinade and the remaining 1/4 tsp. salt.
6. Reduce heat to medium and cook, stirring occasionally, unti chicken is cooked thoroughly, 5-7 minutes more.
7. Serve with sprinkled parsley.