1. Stem and seed yellow banana and Hungarian peppers (or chilies). Cut banana peppers into 1/2-inch squares. Finely chop Hungarian pepper.
2. Rinse tomatoes, core, and cut in half crosswise. Gently squeeze out and discard seeds and juice; coarsely chop tomatoes.
3. In a 10- to 12-inch nonstick frying pan over high heat, combine oil, onion, all the peppers, and half the tomatoes. Stir often until vegetables are tinged with brown and all liquid evaporates, 7 to 9 minutes.
4. Meanwhile, in a bowl, beat eggs to blend with 2 tablespoons water, 1/2 teaspoon salt, and 1/8 teaspoon pepper.
5. Add egg mixture to vegetables and reduce heat to medium-low. With a wide spatula, lift cooked portion of eggs to allow uncooked portion to flow underneath until eggs are softly set, 1 to 2 minutes. Transfer to plates. Garnish with remaining tomatoes. Add salt and pepper to taste.