Toast bagel halves. Divide and set aside the spinach leaves, avocado slices, grape tomatoes slices, and red onion slices into 8 sections- each part goes for each bagel half.
To make the basil pesto, combine the basil, toasted walnuts, garlic, lemon juice, sea salt, and freshly ground black pepper in a food processor. While processing, slowly drizzle in 1 teaspoon olive oil.
On each bagel half, spread basil pesto and layer with spinach leaves, avocado slices, sliced tomatoes, and sliced red onion. Enjoy!
If you don’t have a food processor, you might be able to put the ingredients one at a time in a blender, starting with the liquids and walnuts and garlic, and then adding the rest.