Put a large pan of water on to boil, with an optional pinch of salt. Add pasta when boiling angrily. Just before it's done, scoop out a half mugful of cooking water, and put to one side.
Snip the salmon into ribbons with scissors.
In a little frying pan over a medium heat, once the pasta is cooking and not before, add a lick of oil and throw in your peas and then spinach. Let it wilt but not completely go to mush.
Stir in the pesto and creme fraiche. Add the smoked salmon.
Season, stir and turn off heat. All you want to do is heat through.
Once the pasta is done, drain (reserving a little cooking water remember), and tip it into the frying pan (or vice versa). Mix well, squeeze a little lemon if you like. Season, and add a small splash of pasta water - this will stop if going sticky or claggy. Mix again.
Serve immediately with copious amounts of parmesan.