Step 1 Cook spaghetti in a large saucepan of boiling water according to packet instructions, or until al dente, adding beans in last 2 minutes of cooking time. Drain well, reserving 1/4 cup cooking liquid.
Step 2 Meanwhile, place a large non-stick frying pan over medium-high heat. Cook onion, stirring occasionally, for 5 minutes, or until softened. Add garlic, lemon zest and chilli. Cook for 1 more minute.
Step 3 Add pasta and beans, rocket, lemon juice, olive oil and 1-2 tablespoons pasta cooking liquid to frying pan. Add smoked salmon, toss to combine and season with freshly ground black pepper. Divide pasta between serving bowls and serve topped with crumbled ricotta.