Preheat oven to 350 degrees.

Line a sheet pan with foil or parchment paper.

Stack several slices of bread on top of each other, cut the crusts off, and then cut into 4 squares. Repeat until all bread is sliced into squares.

Lay the squares onto the prepared sheet pan.

Melt the butter in a small microwave-safe bowl in the microwave, then stir in the paprika and salt.

Use a pastry brush to paint a layer of the paprika-butter mixture onto each toast.

Bake toasts in preheated oven for 10 minutes. Remove and let cool.

Add red onion, lime zest, lime juice, cilantro, and 3 tablespoons of mayonnaise to a medium bowl, and stir to combine.

Rinse the crab meat gently in a colander under cold water.
Pick up small handfuls of crab at a time and squeeze gently to ring out water and feel for any shells. Pick out any shells you might find, then add crabmeat to bowl.

Add additional tablespoon of mayonnaise if mixture is not creamy enough.

Add salt and pepper, taste, and adjust seasoning as necessary.

Top each paprika toast with a spoonful of crab salad, then garnish with additional red onion and cilantro, if desired.