Melt butter with olive oil in heavy, large skillet over medium heat. Add shallots and garlic; saute 3 minutes. Add tomatoes and cook just until tender about 5 minutes. Increase heat to medium-high. Add wine, clam juice, lemon juice and marjoram; simmer 5 minutes. Add salmon and simmer until almost cooked through, stirring occasionally, about 5 minutes. Add capers and fresh herbs. Simmer until salmon is just cooked through, about 2 minutes. Season to taste with salt and pepper.
Meanwhile cook gf linguini per package instructions. Drain pasta and return to pot. Add salmon mixture to pasta and toss to coat. Serve.
Bring water to boil for pasta while you are cooking the salmon mixture.