Toss the tomato and pepper chunks with 1 tablespoon of olive oil on a large rimmed baking sheet. Roast for 25 minutes, stirring halfway through, then stir in the almonds and roast for 5 minutes more, until the almonds are toasted. (Be careful not to leave them in the oven for longer than this—they will burn!) Remove from the oven and allow to cool slightly.
Transfer the peppers, tomatoes, and almonds to a food processor and add the remaining tablespoon of olive oil, garlic, and a teaspoon of harissa. Process until smooth. Season to taste with salt and pepper. Add additional harissa 1 teaspoon at a time until the sauce reaches your desired level of spiciness. (Because brands of harissa vary a great deal in spice level, it's best to be conservative! I use Mina harissa and 1 tablespoon is perfect.)
If you don't have harissa, any hot sauce you have on hand will work in this. A few pinches of red pepper flakes can be substituted for the harissa too.