Chilled Pappa Al Pomodoro With Crab Meat Crostini

• 1 1/2 day old bread torn up
• 1 lemon
• 750 gr overripe tomatoes cores removed
• 130 gr crab meat (fresh)
• 30 ml extra-virgin olive oil (plus)
• 8 gr basil leaves (fresh)
• 3 gr pepper flakes (crushed red)
• 4 slices baguette
• 2 slices scallions thinly (sliced)