Heat your grill to high. No grill? Just set your oven to its highest setting.
Trim the beans. Scatter them on a baking tray. Toss with 1 tsp oil. Season well with salt and pepper. Grill (or roast) for 8-10 mins till just tender and starting to char.
While the beans grill, grate the garlic and the lemon zest into a small bowl. Add the tahini and 2 tbsp juice from your lemon. Stir in 1 tbsp oil and 2 tbsp water. Season to taste.
Drain and rinse the chickpeas. Tip into a large bowl. Use a veg peeler to make thin carrot ribbons. Thinly slice the core of the carrot. Add to the bowl with the charred French beans. Pour in half the dressing. Toss to mix.
Peel and thinly slice the shallots. Tip into a separate bowl. Squeeze over the remaining lemon juice. Toss to mix.
Spoon the salad onto two plates. Scatter over the lemony shallots. Drizzle or dollop over the remaining dressing to serve.