Combine 64 ounces (1/2 gallon) water with 1 tablespoon salt in a large pot and bring to a hard rolling boil. Add the linguine and cook until al dente according to the package directions.
While the pasta cooks, heat a large saute pan over high heat until smoking, about 2 minutes. Add the olive oil and heat until shimmering, about 20 seconds. Add the garlic and shallot and cook, stirring vigorously, until fragrant, about 1 minute. Add the sambal, lemon juice, shrimp and 1/2 teaspoon salt and cook, tossing, until the shrimp start to turn opaque, about 2 minutes. Add the butter, reduce the heat to medium and cook until the sauce is thickened, about 1 minute.
The pasta should be al dente about now. Set aside 3 tablespoons of the pasta water, then drain the linguine; transfer both to the saute pan and cook over medium high heat, tossing, until mixed thoroughly.
Remove from the heat and plate the pasta high and tight in the center. Garnish with the scallions directly on the pasta, then garnish that with the breadcrumbs. Enjoy!