Put the goat cheese, yogurt, 1/4 red bell pepper, lemon zest, garlic, salt, pepper, oregano, and the mint in a food processor and puree until smooth. Transfer the goat cheese mixture to a resealable plastic bag and cut a small hole in the corner. Lay out the cucumber circles and squeeze a little of the goat cheese mixture out of the bag on top of each circle. Thinly slice the remaining 1/4 red bell pepper and garnish each cucumber with 1 slice of the pepper. Arrange them on a serving platter and serve.