Heat your sesame oil on medium heat, and sautee your aromatics -- garlic, shallots, lemongrass and ginger -- in the oil until they are fragrant.
Add your mushrooms and selected vegetables, coating evenly with the mixture for just a minute, prior to adding your red curry paste. Once the curry paste is in the mix, you want to ensure that it also coats the vegetables evenly and that you give it and the vegetables some time, about 5 - 7 minutes, to cook. Be sure not to overcook the vegetables, as they will cook further with the salmon.
Add in your coconut milk! It will turn everything into a beautiful pink color that will quickly begin to boil if left on too high a temperature. Bring to a high simmer, add in your salmon, along with the fish sauce. Cover and cook on medium heat for another 5 - 7 minutes.
Garnish with basil, lime and lime juice, and serve with steaming rice.