In a large skillet, heat 1 tbsp. oil over medium-high. Add the bread and toast until browned, 30 to 60 seconds per side. Let cool. Cut into 1/2-inch cubes. (You should have about 1 cup.)
Wipe the skillet clean with a paper towel; add about 2 tbsp. oil and heat over medium high. When the oil begins to shimmer, add the almonds and garlic. Cook, stirring often, until the garlic is golden and the almonds are aromatic, 1 to 2 minutes. Add the peppers and paprika; season with sea salt. Cook, stirring often, until heated through, about 1 minute. Pour into a food processor. Add the bread cubes and vinegar and process to desired consistency (some people like their romesco a bit chunkier, some super smooth), 30 to 60 seconds. Season with more salt, vinegar, or olive oil to your liking. Cover and refrigerate until flavors meld, 3 to 4 hours. Store in the refrigerator up to 1 week.