Bring a medium saucepan of salted water to the boil for the spaghetti. Crush or finely chop the garlic. Finely grate the zest of half the lemon*, then juice the half. Halve the tomatoes.
Step 2 — Finish prep
Discard the husk and silks from the corn, then slice the kernels from the cob. Separate the smoked salmon slices, then coarsely tear into pieces.
Step 3 — Cook spaghetti
Add three-quarters of the spaghetti* to the pan of boiling water (if you're tempted to throw in all the spaghetti, just note the dish won't be as saucy). Cook, stirring occasionally, for 12 mins or until al dente. Reserve 2 tbs cooking water, then drain the spaghetti.
Step 4 — Start sauce
While the spaghetti is cooking, heat 2 tbs olive oil in a medium deep frypan over medium heat. Cook the garlic, lemon zest and 2 tsp Italian seasoning*, stirring, for 1 min or until fragrant. Add the tomatoes and cook, stirring occasionally, for 5 mins or until beginning to break down.
Step 5 — Finish sauce
Add the corn to the sauce and cook, stirring, for 3 mins or until tender. Remove the pan from the heat. Roughly mash the tomatoes with a fork to release their juice. Stir the reserved cooking water and 1 tsp lemon juice* into the sauce. Taste, then season with salt and pepper.
Step 6 — Get ready to serve
Thinly slice the spring onion. Add the spaghetti and smoked salmon to the sauce and toss to combine. Divide the spaghetti among plates and scatter with the spring onion to serve.