Step 1

Prepare a grill for medium heat. Rub salmon with 2 Tbsp. olive oil; season both sides with kosher salt.

Step 2

Cut ends off lemon and discard. Set lemon upright on a cutting board and slice off 4 lobes, working around the core (the seeds will be left behind). Finely chop lobes (flesh, pith, and all) and transfer to a small bowl; you should have about 1/3 cup. Squeeze juice from core into bowl; discard core. Add shallot, sesame seeds, honey, sesame oil, and 1/3 cup olive oil; season with kosher salt and lots of pepper. Toss to combine.

Step 3

Clean and oil grate, then immediately place salmon on grill, skin side down. Cover and grill, without turning, until skin is lightly charred and flesh is opaque all the way through, 6–8 minutes. Transfer salmon to shallow bowls or plates; let cool slightly. Spoon sauce over salmon. Top with basil; sprinkle with sea salt.