Place the halved yellow tomatoes, quartered onion, garlic cloves, and chopped jalapeño on a baking sheet. Drizzle with olive oil and sprinkle with salt.
Roast in the oven for about 20 minutes, or until the tomatoes and onions are soft and slightly charred.
Remove from the oven and let cool for a few minutes.
Transfer the roasted vegetables to a blender. Add the chopped cilantro and lime juice. Blend until smooth.
Taste and adjust seasoning if necessary. Serve with tortilla chips or as a topping for tacos.