Heat olive oil in a pan over medium-high heat.
Once the oil is hot, add salmon, salt, pepper, paprika, and lime juice to the pan and saute for 3-4 minutes, stirring frequently.
Melt butter in a large saucepan over medium heat.
Add flour to the pan and whisk for 1 minute, until the flour is lightly browned.
Reduce the heat to low. Slowly pour in 1 cup of whole milk, while whisking constantly, until combined and smooth.
Add salt, black pepper, paprika, cheddar cheese, and gruyere cheese and mix well, until combined.
Stir in another 1 and ½ cup of whole milk and whisk until the sauce is creamy and smooth. Remove the pan from the heat.
Add the cooked pasta to the pan with the cheese sauce along with cooked salmon and stir well to combine. Pour the pasta mixture into the prepared baking dish. Top with sharp cheddar cheese and gruyere chesee
Preheat the oven to 325 degrees F and grease a 9×8 inch baking dish. Keep the baking dish in the middle rack of the oven and bake for 15-20 minutes, until the chees is bubbly and lightly golden brown.
Remove the tray from the oven. Dish out the pasta onto serving plates and serve hot.