Ottolenghi found inspiration for this salad from "Ingen no goma-ae," Japanese green beans with ground sesame and miso. He then blows apart the Japanese flavors by making use of tahini in the sauce.
Trim off any leaves from the broccolini. If the stalks are thick cut them lengthways into two or four, so you are left with long and thinner stalks, similar in size to the green beans. Trim off the stalk ends of the beans and snow peas, keeping them separate.
Bring a medium pan of unsalted water to the boil. Blanch the green beans for 3 to 5 minutes, or until just tender but still crunchy. Lift into a colander and refresh under running cold water; drain and dry well with a tea towel. In the same water blah the snow peas for 2 minutes; refresh, drain and dry. Repeat the process with the Broccolini, blanching it for 2 to 3 minutes.
Mix all the vegetables together in a bowl with the oil. You can now serve the salad in two ways. For one, stir most of the cilantro leaves and sesame and nigella seeds in with the vegetables and pile up on a serving dish; pour the sauce on top and finish with the remaining cilantro and seeds. Alternatively, pile the vegetables on a serving plate, dotting with cilantro leaves and sprinkling with seeds as you go; serve the sauce in a bowl on the side.