Soak beans overnight.
Rinse and simmer beans for about 30 minutes until soft but not mushy, drain and set aside.
Preheat oven to 350 F (180 C).
Chop vegetables and then in a large bowl mix the peppers, grated onion, garlic, beans, olive oil, tomato paste mixture, oregano, and pepper. Mix gently as to not break the beans.
Add the halved cherry tomatoes and mix gently.
Pour into casserole dish.
Add ¼ cup hot water to the dish pouring it in a corner and tilting the dish so that the water spreads (do not pour over as this will wash off the olive oil).
Cover with aluminum foil and roast for about 1 hour until peppers are soft.
Remove foil and roast for about 10 minutes if you want some browning. Be careful not to leave it uncovered too long, otherwise the beans will dry out.
Remove from oven, let it cool and add thick salt as needed.
Serve plain or with feta cheese.