Using gloves, cut-off the stems of the chili peppers (both kinds) and remove the seeds. Transfer to a blender. Add the garlic, maple syrup, apple cider vinegar, oil, salt, and water. Add the tomato as well. Blend on high speed for 10-20 seconds, or until smooth.
Strain the juice through a fine sieve to remove the chili seeds and skins. Note: You can discard the pulp or use in stir-fries or marinades to add spiciness.
Transfer the strained juice to a saucepan and bring to a boil. Reduce the heat and let simmer uncovered for 7-10 minutes, or until it has slightly thickened and doesn't smell like raw peppers anymore. It will also get a slightly deeper red color.
Stir in the diluted cornstarch, and whisk until the sauce has thickened. Remove from heat and transfer to a clean jar. You can also let it cool completely and then transfer to a squeeze bottle.
Store in the refrigerator for up to 10 days. Use this sweet chili sauce as a dipping sauce for egg rolls, potato fries, steamed veggies, or drizzle on rice, noodles, spring rolls, pizza, and more!