Place water, stock and reserved juice from tinned clams into a medium saucepan. Set over medium-high heat; bring to a boil then reduce heat to low.
In a large pot or deep frypan, melt butter over medium heat. Stir in onion and cook until softened, stirring occasionally, about 10 minutes. Stir in rice and cook, stirring, for 3 to 5 minutes. Do not let rice brown. Pour in wine and cook, stirring until the wine has evaporated. Add 1/2 cup of simmering broth and stir until the broth is almost all evaporated. Then add another 1/2 cup of broth. Stir in saffron and basil. Continue adding broth 1/2 cup at a time and stirring until the liquid has evaporated until the rice is almost al dente, about 20 minutes.
When the inside of the rice is slightly more firm than you desire in the final dish, stir in clams, flaked salmon and 1/2 cup broth. Stir until the liquid evaporates. Season with salt and pepper. Stir in 1/2 cup broth and stir vigorously. Remove from heat before the liquid has completely evaporated.