Pour the chickpeas into a sieve, rinse with cold water and drain well. Peel onions and cut them into fine rings. Wash, clean and halve or quarter the tomatoes. Wash chives, shake dry, put 4 stalks aside for garnishing.
Cut the rest of the chives into small rolls. Drain mozzarella and cut into slices. For the vinaigrette, mix vinegar, salt, pepper, sugar and pesto. Fold in the oil. Mix peas, chives, onions, tomatoes and vinaigrette.
Spread the mozzarella on four portion plates, arrange the salad on top. Garnish with 1 chive stalk each. Flatbread tastes good with it.