Preheat the oven to 350 degrees F. Arrange the bread and almonds on a baking sheet, and bake, flipping the bread once, until it is toasted and crunchy and the almonds are golden, about 10 minutes. Set aside to cool.
Meanwhile, put the vinegar, orange juice and zest, oil and 1/4 teaspoon salt in a jar or other container with a lid. Secure the lid, and shake until combined. (The vinaigrette can be made a day ahead; shake well before serving.)
Put an avocado quarter on each slice of toast, and mash and spread the avocado with a fork to cover. Quarter each piece of toast, and arrange the pieces on 4 plates with the points facing out to make a square.
Toss the arugula, toasted almonds, feta, radishes and vinaigrette in a medium bowl. Taste and adjust seasoning with salt if necessary. Put a mound of salad on top of each avocado toast square. Quarter the remaining orange half, and garnish each salad with a piece.
Copyright 2015 Television Food Network, G.P. All rights reserved.