Preheat oven to 375; line baking sheet with silpat or foil sprayed with cooking spray; set aside.
Slice bagels carefully. You should be able to get about 5 slices from each bagel. It's okay to get more or less!
Melt the butter, if using. If not, skip to next step.
Brush bagel slices, front and back, with olive oil; alternatively, spray the slices lightly front and back with cooking spray.
Line bagel slices on baking sheet in an even layer.
Sprinkle with salt.
Bake for about 16 minutes, flipping the chips over at 8 minutes.
I recommend starting to check at about 14 minutes of total cook time to see how they're crisping up - you can then manage how crispy you want them!
When done, remove from oven and set aside while you make the dip.