Step 1

Put a large saucepan of water on to boil.

Step 2

Spiralize squash and zucchini into medium-thick "noodles." (Alternatively, cut them lengthwise into long, thin strips with a vegetable peeler. Stop when you reach the seeds in the middle--seeds make the strips fall apart.) Place the vegetable noodles and corn in a large colander.

Step 3

Cook soba noodles in the boiling water according to package directions. Pour over the vegetables in the colander to drain.

Step 4

Meanwhile, combine ponzu, tahini, oil, vinegar and salt in a large bowl.

Step 5

Add the soba and vegetable noodles to the bowl along with tomatoes and scallions. Toss to combine. Serve topped with sesame seeds.