I first made this pasta with an embarrassment of leftover riches from Grilled Salmon Niçoise Salad and Elotes, but with most of the ingredients cooked on the grill, it's almost as easy to prepare from scratch.
Preheat grill to high (about 400-500°F). Place the salmon skin-side down on a double layer of aluminum foil. Sprinkle generously with salt and pepper and lay the lemon slices over the flesh. Grill salmon on one side of grill until done to your liking, about 8-10 minutes for just barely opaque in the center, depending on thickness. Meanwhile, place shucked corn directly on grates on available side of grill and grill until nicely browned but still tender, flipping once, about 5 minutes per side,
When grill is free, rub asparagus with the olive oil, sprinkle with salt and pepper, and grill until nicely charred, 2-3 minutes per side, flipping once.
Cook spaghetti al dente according to package directions. Drain and toss with pesto. Flake the salmon into bite-sized pieces, cut corn kernels from cobs, and gently mix salmon and corn into pasta. Divide pasta among serving bowls and garnish each with a few olives, some asparagus spears and a grilled lemon slice. Serve with grated cheese to pass at the table.