Easy Pimento Cheese

1/2 pound Cheddar cheese, shredded (recommended: Colby)

1/2 pound Pepper Jack cheese, shredded

One 4-ounce jar diced pimentos, plus 2 tablespoons juice

1/2 red onion, diced

1 cup mayonnaise

3 cloves garlic, finely minced

1 teaspoon hot smoked paprika

1/2 teaspoon ground celery seed

Salt and freshly ground black pepper

1 loaf white sandwich bread, sliced into diagonal pieces