Thinly slice a baguette; arrange in a single layer on a baking sheet. Brush with olive oil and sprinkle with salt. Bake at 425 degrees F until lightly golden, about 7 minutes. Let cool slightly.
Toss 1/2 pound peeled shrimp with 1 tablespoon each chopped chives and parsley, 1 teaspoon each red pepper flakes and lemon zest, 1/2 teaspoon paprika, a drizzle of olive oil and a pinch of cayenne. Grill 2 to 3 minutes per side. Spread marinara sauce on the toast rounds. Top with the shrimp; drizzle with olive oil and sprinkle with chopped chives.