Preheat oven to 400°F (200°C) and line a small baking sheet with parchment paper.
Rinse and pat the chickpeas very dry with a paper towel, then toss with a half-teaspoon of olive oil and a pinch of salt.
Roast the chickpeas for 20 minutes, shaking the pan halfway through, until they are golden and crisp.
Season the chicken breast with salt and pepper, then grill over medium-high heat for 6-7 minutes per side until the internal temperature reaches 165°F.
Let the chicken rest for 5 minutes before slicing into thin strips.
In a small jar or bowl, whisk together the remaining teaspoon of olive oil, tahini, and lemon juice until smooth.
Combine the mixed greens, cherry tomatoes, and sliced cucumber in a large salad bowl.
Top the greens with the sliced grilled chicken and roasted chickpeas, then drizzle the lemon-tahini dressing over the top before serving.