Make the vinaigrette:
Combine the olive oil and the grated garlic in a small saucepan. Cook over low heat until the garlic begins to brown slightly, about 10 min. Add a pinch of salt and stir to dissolve. Remove from the heat and let sit until the oil cools a bit, about 3 min. Add the paprika and let it infuse the oil for about 12 min. more. Strain the oil through a fine sieve and discard the garlic. (If making in advance, store in the refrigerator for up to 2 days.)
Put the vinegar in a small bowl. Add a pinch of salt and a couple of grinds of black pepper and whisk to combine. Slowly drizzle in the garlic-paprika oil, whisking constantly until well incorporated. Taste and adjust the seasonings if necessary.
Make the salad:
Prepare a medium-high charcoal or gas grill fire. Brush the corn all over with olive oil and season with salt. Grill, covered, turning occasionally until all sides are charred and deeply blistered in places, 6 to 10 min. Remove from the grill, cut the kernels off the cobs while still warm, and put the kernels in a large bowl. Add half the vinaigrette and toss to coat the kernels. Stir in the scallions and set aside.
Reduce the grill temperature to medium, or if using charcoal, let the coals die down a bit. Grill the shrimp and the sausage, turning once halfway through the cooking time, until the shrimp are pink, curled, and cooked through, 4 to 6 min., and the sausages are plump and well browned, 5 to 8 min. Transfer the shrimp and sausages to separate platters and cover with foil to keep warm.
While still warm, peel the shrimp and gently fold into the salad, along with the rest of the vinaigrette. Slice the sausages into 1/3-inch-thick half-moon-shaped pieces and mix into the salad. Add the tomatoes and mix gently. Taste and season with pepper and more salt if necessary. Serve the salad warm or at room temperature spooned over slices of grilled garlic bread.