Heat the oven to 375°F. Lightly grease the cups of a standard 12-cup muffin pan with the olive oil.
Put the couscous in a small bowl and pour the boiling water over it. Cover and let it stand for 5 minutes, then fluff it with a fork and let it cool slightly.
In a large bowl, combine the ground beef, couscous, roasted red peppers, feta, egg, onion, garlic, oregano, salt, and black pepper. Mix gently until evenly combined, taking care not to pack the mixture too tightly.
Divide the mixture among 8 muffin cups, mounding it slightly. Spread a little tomato paste over the top of each portion.
Bake until the centers reach 160°F, about 20 to 25 minutes. Let the muffins rest in the pan for 5 minutes before lifting them out.